Somebody mentioned this earlier and I'll expound on it a little bit more... You can definitely get a good guitar solo out of biab in it's present state by compositing solos (I'm talking about version 2010)... Basically you have to generate as many solos as it takes and under different chord progressions, then export all those solos to a daw program... Putting each in a separate track and stacking them, you then go through each individual solo, muting the parts you don't like and keeping the parts you do like... You may have to cut and paste some parts... After a while, you will come up with a good solo...

Also, used judiciously, great solos can obtained from the metal guitar soloists...

I would strongly recommend springing for the latest biab since the soloists there will help achieve what you want... Also, the ability to automatically port files over to your daw will help immensely with time issues...

Just my 2 cents...