keeper league options/rules??

[dc2233]

Our 5X5 roto league wants to change to a keeper league this year (obviously not carrying over from last year). It is a 12 team league with a snake draft (can't get all the ducks in a row for an auction). I am just looking for some different/interesting/cool ways (or rules) to run the league. we definitely don't want the superstars eligible as keepers but I wanted something a little more complicated and interesting than just saying any player drafted after the 5th round is eligible.
Any ideas/suggestions are appreciated.