The use of game engines has increased quite a bit over the last couple years; there are now something like 250 that support Windows. (And maybe five to ten that are important commercially.)
It's tempting to consider focusing some effort on supporting a few of them better in Wine, on the theory that then games built with those engines would stand a better chance of running on Wine.
The two main commercial ones with freely downloadable SDKs that I know about are Unity3D ( http://appdb.winehq.org/objectManager.php?sClass=version&iId=19268 ) and Unreal ( Unreal's UDK requires .net 3.5, so it can't be installed at the moment ).
Looks like Unity3D is close to working, according to the appdb. I'm afraid to guess how long it'll be before we can even install Unreal's UDK...
I've written up a few notes and links on the subject at http://wiki.winehq.org/GameEngines - Dan