no development going on AFAIK.

you can get 1280x1024 by adding the correct lines to the com.apple.Boot.plist file in /Library/Preferences/SystemConfiguration/ e.g.
<key>Graphics Mode</key>
<string>1280x1024x32</string>

I've bought a cheap supported card, because it doesn't look like the x1250 will be supported anytime soon.