What is the state of SPICE these days? The official site is pretty stale. About a year ago I tried to virtualize my desktop with KVM/SPICE but I found the performance pretty bad. And the clients sucked big time. The best one was on Windows, but that's not of much use to me because I run a Linux-only shop at home. The Linux clients didin't do mouse scroll wheel. There's also an Android client but it seems like a one-off effort because it hasn't seen any updates in quite a while. Ideally, I would have a small Android PC (they are getting quite popular and powerful these days) next to my display and everything should run on the server tucked away.
I think SPICE holds much promise. I hope it materializes soon.