I ran across another intriguing flat bar alternative. There are many mountain bike handlebars out there, with many having 3 to 9 degree rises and sweeps. Far too many to mention, you can peruse them at many of the bike part outlets, such as Jenson USA.

I came across one that is sold as a downhill racer bar, but could easily be used as a more comfortable alternative to a flat bar. The company is Syntace, the product is their Vector Downhill 7075 handlebar. It is available in two widths, 660mm and 700mm (both can be cut down to as short as 580mm), and three sweep angles. They offer it in 6, 12, and 16 degree sweep angles. I like sweep angles of 15-20 degrees, find them quite comfy. Most MTB bars don't offer this much sweep.

This bar has a 33mm rise, but they also offer an almost identical bar with a 13mm rise with either a 12 degree or 16 degree sweep, if one prefers a flatter bar.

I haven't had a chance to try one, but would like to.

http://www.syntace.com/index.cfm?pid=3&pk=362

The one pictured is the 33mm rise with 12 degree sweep.