I really like Wulf's idea, although I'd want to tweak it a little bit. As written it leads to (on average) 24-point-buy characters. The highest anyone is likely to get would be a fairly boring 30-point character (18, 12, 12, 10, 10, 10 or 18, 14, 10, 10, 10, 10).
I think this could be fixed with two modifications:
1) People can only use the +2 cards to get a score up to 16.
2) Folks get two special cards, which can gain extra treasure, an extra feat, extra skill points, or +1 on any stat (which can raise a stat above 16).
That would put a regular character up to 26 points, or a minmaxed character up to 34 points (18, 16, 10, 10, 10, 10). A normally minmaxed would be 32 points (18, 14, 12, 10, 10, 10), which is the norm for a high-powered campaign. And the 34-point character would have such dull stats that I'm guessing most folks wouldn't go for it.
Still, I like the idea!
Daniel