LOTS of really good stuff here. Sorry I'm late.
NASA does some things right but they haven't got it all figured out. Their real strength is in in the ability of the HPDE program to grow people into race licenses - something that SCCA has completely missed the boat on.[/b]
I'm repeating this, because it's such a fundamental issue. In fact, I see this as the single largest opportunity for new membership, and as Kirk said, the SCCA hasn't got a clue. Someone mentioned PDX as an answer, which it might be, but I think it only goes part way.
I think NASA has it right (and they sure didn't come up w/ it, EMRA had it 20 years ago when I got hooked on this madness). You have to run your HPDE/Time Trial/Solo I events IN CONJUNCTION with a race. It's an association thing. You get people out there w/ their street cars intermingled w/ people w/ their race cars, and the street car people get exposed to what the whole racing side is all about. You've got a Wombat XSR that you drive to work every day, and Fred (Bob's brother and Alice's cousin) has a Wombat XSR that he trailers to the track and races. You start checking out Fred's car, and talking to him about what he's done w/ it, and then you hang around and watch him race it. THAT is what will get people hooked. I know, because it's exactly what happened to me. I took my Rabbit GTI street car to Pocono for an EMRA Time Trial and there were these two guys there w/a a Rabbit GTI that they were racing. It took that, and one session on the track at speed, and I was ready to sign up!
And please, stop trotting out the red herring that is the 'wing thing' to attract the tuner crowd. You need to actually look at the typical 'tuner guy' mindset to understand that the vast majority of them will never make the jump to racing. And it's not because they can't put wings on their race cars. For most of them, it's not just about the go-fast stuff, it's about the BLING. And the biggest issue, is that they don't see their cars as disposable. By that I mean, they're not comfortable (or willing to accept) the fact that they may write their car off any time they put it on the track. Hell, some of them still owe major chunks of money on their cars. If you don't believe this, just scan any of the marque forums and look for the stories about how the kid totaled his Wombat XSR at the track and his insurance company is denying coverage and how he now has no car but still has to pay for it.
You want to get the tuner crowd hooked on racing, start having HPDEs in conjunction w/ races, and work VERY hard at educating them as to what you can and can't do to the cars. It's one thing to talk about it, but when you've got physical examples right there, it's easier to get the message across.
Kirk, and others, have made some very good points about older cars in IT. Looking at the 'age window' when IT was created provides good insight into what was going on at the time. There's a reason that they made an age cutoff. I just wish that they would have had the vision to put something in there about how to deal w/ it in 10, 20, ??? years. That being said, I don't want to see anyone told that the car they have will no longer be eligible to race because it's too old. I think Evan really hit on something. Don't issue new log books to anything older than 25 (20?) years old, but grandfather in all the cars that currently have log books. I think that solution strikes a good balance between the two issues. Of course, there will be the case where someone wads up their 1980 Puddlebee, and has three spare tubs at home and a garage full of parts to build another one. I think in that case, you just have to say "No". There is of course the 'transplanted roll cage' option.
As for creating 'newer' IT cars, and better aligning T and IT, I think it's a great idea. Do you go so far as to say that you can prep to IT rules, cars that are <5 years old, and race them? I'm not sure. Maybe. I think it's probably better to make the T rules a true sub-set of the IT rules. For example, only stock parts, no gutting of the interior, remain emission-compliant, etc. for T (probably not too far from what the original IT rules were). I just threw those out there as a couple of examples, certainly not a complete list, and may need to be tweaked further.
An important part would be to roll T and SS into one category. Right now, most of the T3 cars are ITR and some ITS cars. You need ITA and ITB (ITC???) cars. Set up T1 - T5 and be done with it. And don't let the mfg's hold the Club hostage again. I also think the T -> IT progression needs to be codified. And that being said, I don't really see a way of creating a T>IT>Prod>GT progression scheme, at least not the way things are now. Look at EP, it's a mix of ITA and ITS cars, nothing faster. And find something that's less than 10 years old that would fit into HP. GT has gone way too far down the tube-frame road to ever make it reasonable to build one out of a tub car. Not only that, just look at how many guys moved from Prod to GT over the last 10 years (w/ the same car) to get a sense of the desire for such a progression. I think that while it may look good on paper, and it may have this ultra-strategic ring to it, there's no real practicality in it. Nor is it something that the membership may really want.
And I won't go into my thoughts on the whole Regional/National thing again. I've made my position very well known on that issue.
And as Greg said, one of the important things to do, is not dork up IT. I think the ITAC have done a good job in balancing the need to fix some issues w/o going too far and just opening the flood gates (ECU issue notwithstanding).
It's really too bad that we can't drive a bottom up strategic plan for IT. And it can't be done in isolation, it needs to be part of a larger plan for all of the production-based categories, and Club Racing as a whole, above that.
My 5-year vision for what the production-based landscape will look like:
Prod pretty much is gone
BP/DP (and probably AP and CP) are the 'new' GT
T1-5 align w/ ITR-C (not directly, but you get the point from my post above)
SS is gone
Regional/National distinction is gone.
ITR, S, and A have the largest fields at the Runoffs.
SM is gone, as all but three of the cars have been wadded up.
The one key area that I didn't mention above is AWD/forced induction. SOMETHING will need to be done to get those cars into IT. The mfg's are offereing more and more cars w/ this configuration. They're already in T. Not finding someplace for them in IT will be a big mistake.
when they did it to each other. 
