by Jude
Thanks to you both for your quick answers. I have been playing a couple of solitaire variants:http://www.boardgamegeek.com/thread/1105640/new-solo-variant
and
http://www.boardgamegeek.com/filepage/92787/dc-comics-dbg-so...
which change the rules somewhat, so I was thinking in terms of their rules (which do have villains attacking and a Main deck discard pile.
I should have posted my questions in the variant thread.