There are some Mids that have been mentioned such as the Kite and Panther that have a driver-like design. However all the ones I am aware of are understable, so if you didn't like the way the Roc flipped you are not going to like these at all.
The Millennium Sentinel MF is more overstable than a Roc, and the top of it is more tapered from the wing to the center of the top. It's hard to explain, but it is sort of like a driver top on a midrange bottom. So it might feel more like a driver, and it will handle more snap than a Roc. So that is what I'd recommend.
As for grips, I use a fork grip on putts and midrange shots. I spread my fingers more on a putt, but for midranges I use pretty much the classic fork grip with my last three fingers pressed together against the rim. I also use the power grip, but only on drivers. I really can't get a power grip to feel comfortable on my midrange discs.