Here's what people on linux-kernel and comp.os.linux.development.system have been suggesting.
Some items are rather hotly debated.
I'd like to thank everybody who offered suggestions and corrections to this list. I'm also listing who's working on what, if I know about it. If you want to drop me a line with additional info, I'll put it in. This might be your E-Mail address, or the URL for a patch that people may try out. Also, please be aware that not everything listed here necessarily is a good idea.