I'm the same way about missing album art, it drives me mad. But I'm not much of a one for photoshopping, so I just use a picture of the group that I like for the bootleg covers.
Like a Tusk era shot for a Tusk tour show:
http://tinyurl.com/3gt5cpg
That works for me right now, but I'd love some great looking covers for these shows. Especially since there seems to be alot of talented artistic types around here. So, yeah, not a stupid idea at all!
BTW, I've downloaded the few shows I have from this board, but I never thought to check throwndown.net for covers. Gonna go check that out.