As much as I like Mike's S-Gear client for Win/Mac I agree that asking the amp sim to also serve as a VST/AU host is not the ideal approach. I evaluated Cantible, Gig Performer, Reaper, Main Stage and have settled on Ableton Live to host S-Gear. This solution provides me with a simple way to map my FCB1010 pedals to parameters in S-Gear as well as plugins and I'm able to use Ableton's track volume and routing and even record. Having 8 instances of S-Gear running allows me to instantaneously switch presets without any audio glitches.
The support issues involved in supporting the vst host approach would be substantial and I'd much rather have Mike focus on continuing to improve the amps.