Hello Thlorenz and Rob,
I was indeed planning to add this to ViEmu 2.5, but I've had to drop it or I would never finish it. I will add it in later. ViEmu 2.5 does have multiple-key mappings and a few other exciting features. It's now basically finished, and as soon as I finish catching up with the pending support requests here and over email, I will put together and publish a pre-release test version (since it includes the new licensing system, I want to do some serious testing before notifying everyone).
The beginning of 2010 has been quite a beast to deal with, but I think I will now be able to start managing everything better and many good things will happen to ViEmu and Codekana in the next few months. Not the least of which the VS2010 versions of both!
Regards,
-- Jon