I was at NAMM this weekend and saw that Fishman has a new internal mic system. I couldn't really tell how it sounds since the event hall is so loud but from what I could tell it seemed ok.
It attaches right to the inside of the top right under the bridge.
They also have a combo setup (mic and undersaddle pickup) that might be interesting but I've never liked the sound of piezo pickups but maybe you can blend the mic in enough to make it work. I think the idea is that the piezo is less suseptable to feedback so you use that for the lows and then use the mic for the highs.
The mic alone I think retails for about 200 and the combo is 300 $US.
Has anyone tried out the internal mic on a gypsy guitar?