I hear you Tim. As you probably know I've been watching the V4B carefully too. While I do think you'll be able to cop a V4-esque tone out of the 100T, I don't think you'll ever get that delicious overdrive/fuzz out of the V4. I could be totally wrong but I don't think I am having owned quite a few Ampeg's.
And that's fine, most don't want/need that level of overdrive the 100T/SB300 offer. Heck, I don't use it much in the band setting either but it sure is fun and helps break the monotony at times.
As much as I love the vintage channel, especially with my flatwound bass, I am more and more using the flats on the active channel and blending in a touch of overdrive on songs that I want to have a clean bass sound. It works rather like an exciter, with the added harmonics giving it a presence in the mix. But the distortion is hidden in ensemble, so it doesn't sound distorted. That's the same thing that's happening with the power tubes sitting on the edge of distortion, except on the preamp side, which is more buzzy, with the power tube distortion being more throaty. So the combination of the two is pretty amazing. Takes a bit of fiddling between overdrive and blend; too much and it sounds distorted, too little and it has no effect. But it sure sounds smooth and present when you get it right. It's the sound I've always tried to get with distortion and overdrive pedals, but it never got there. Mainly because it lacked the power tube grunt.
Also, just to state my affiliation, unless I state otherwise this and everything else I post about the 100T is in regard to using it on stage.

