On a "regular" touring frame I'd stick with the drop bars, raised to saddle height as others have suggested(or the aero bar idea is pretty cool too). You get the hand positions and control along with the added benefit of going low while riding into a headwind, or "bombing" downhill-if you want.
For an "ATB" or "MTB", being a bit more upright anyways, I like the Trekking bar setup seen on many european bikes. I have a similar one from nashbar on my foul weather bike, and the adjustability (up/down) along with the hand positions would seem to work out very well for extended riding. I haven't gone farther than 15miles on it yet though, so can't say for sure.
Nashbar trekking bars-note that these particular bars may, or may not prove sturdy enough for loaded touring. "Real" ones (stronger, varying sizes etc.) could probably be imported through Koga-Miyata, Saint Johns Street Cycles etc.