As you probably already know, I use Bandstand for the styles/midi files and Kontakt for my lead voices. To change voices in Kontakt I set it up such that there is a separate voice for each of the 16 channels. This way you can change voices quickly. Now Kontakt can also accept bank and program changes.

I am still waiting for Garritan's GM wavetable. This has been delayed so they can use their own player, namely, Aria.