Full graphics and audio support?
Well, the Mic doesn't work.......
It's not really full support, but I hacked together graphics drivers for the Radeon 9200 Mobility. No support for sleep, or Airport Extreme, but it runs OS 9 natively.
VirtualPC runs a little better under OS 9 in some cases, as processes can hog the CPU time better than under OS X. I forget the last version that runs under OS 9. The drawbacks, if the app hangs or crashes you'll need to reboot, not so under OS X.
Also, v7 of Virtual PC doesn't have support for little endian, as it will run on the G5, and the G5 lacks mixed endian support.
We are vitalizing a little endian CPU, so it only stands to reason that it's going to be faster with mixed endian support.
In this case, if v7 is running the apps the OP wants to run, and a little more speed isn't really going to help, there is no reason not to just continue to use it under OS X, I just wanted to point out that OS 9 will run native.
I also have the iBook G4 with the Radeon 9550 running OS 9, tho it lacks Graphics Acceleration and sound, I'm sure it will run Virtual PC just fine.