Have you ever tried the Plainfield Fishing Resort for crappies? Not all of them are slabs, but if all you are doing is C & R, there are some decent size ones in there.
Right now, they are hard to find (like most crappies). But late October is an awesome time to go for them. You will find them pretty much all over the lake in brush piles, log jams, etc. There are a couple key areas (call them hotspots if you want) where I fish for them, and they average between 7" and 10". (My personal biggest was 13 1/2".) On an average morning, I can catch anywhere between 8 and 12 of them. On a good day though, I can get as many as 20. I am 100% catch and release, so anything I catch swims again for others to catch later.
Sure, its pay lake ($8.00 per adult for the day), but sometimes its worth the 8 bucks to have some fun.