If I may suggest going back to a post early in this thread, double check the condition of the sidestand switch. A while back someone on this board posted about a stalling problem while riding that turned out to be the sidestand switch vibrating slightly and having just a tiny bit of grime on it, combining to just barely making enough contact to kill the engine even though the warning indicator on the dash did not show "Sidestand Down". No check engine light, no other outward sign that there was a problem.
It just so happened that my bike experienced the exact same problem this morning on the way to work; started fine, pulled away from a stop just fine, then while riding in 2nd gear at between 28-31 mph about to shift into 3rd when the engine dies. This happened several times in a row, I tried various gear/speed variables and it was pretty consistent so I figured it must be related to an engine vibe thing (since noone can read their tach while riding!). Sometimes after it stalled it would not crank nor restart, but sometimes it would. Eventually I recalled the thread about the sidestand being dirty, loose and vibrating and reached beneath my engine and wiped the switch with my gloved finger. Boom, bike started immediately and did not so much as sputter on the rest of the ride. I will give it a more thorough inspection when I get home, but its a simple thing to check out before paying a mechanic.
Where are all the craftsmen gone?