I was at HF a couple of years ago and saw in their discount and discontinued section two containers of steel shot. They were each 25 lbs and came in plastic bottles that were a bit samller then 1 gal. bottles. I picked the two up for $2 each.Lead shot, if you can get it, can be put inside most any shaped container (frame rail, roll cage bar, evap canister etc). Not hard to build a container you can add or subtract the amount of shot inside to give you what you need.
I thought about using them for ballast but at this point I don't need any unless it's helium ballast! LOL