Check these out:
http://www.endless-innovations.com/m...tegory=BarEnds

I've had them a few months, at first I was nervous about them, but they've been stable enough. My LBS tells me that this product has existed before, but disappeared from the market. There also used to be a bar-end that had drops AND MTB grips similar to those posted above, which would be perfect for me, but they disappeared also.

I have not gone whole-hog while holding these things, however, as I have visions of them slipping, or cracking, and me leaving a trail of teeth on the road. I normally go into the drop position, stay seated, and pedal at 80-90 rps, and for this they have felt very stable. I plan on trying the aero-bars eventually, when I'm done fooling with my commuting bike.