Evolution supports a vFolder (Virtual Folder). Basically a vFolder is a query that is ran against your real folders to select messages.
It's useful. What I do now, is have my mail broken up into a number of folders. Each mailing list gets its own folder. Mail from the CS department gets a folder, etc.
Now, I can create a vFolder Inbox that can search those folders for new mail. I can construct even more complicated queries. But here's the problem: with Evolutions GUI you cannot currently construct complicated boolean expressions. Either just a group of expressions combined with AND or combined with OR, but not nested (AND (OR ...) (OR ...) (AND ...))
Evolution does support a generalized S-Expr definition of rules. It's undocumented and I've finally figured it out.

