I had to do it twice too, but now have the same setup you describe with a P4, Audigy, 64MB Video, etc. Quake is a little tougher to play on a 7", but being able to play it is a must.

I ended up using the Opus with a PW-70A for externals, Screen, Hub, and switched with a relay. Works great. Opus alone would have been borderline.