If the plane is tail toward the airport, then he didn't have time to turn around and head back.
Now....from your pilot's view point. Where did he start to take off?
From the intersection of the two runways, or did he go to the very end of the shorter RW and take advantage of the full length.
If he was let's hurry up and beat the traffic to Atlanta....then could he have started from the intersection?
There is a line of clipped trees and fences from the end of the short runway to the crash site - no turn around here.
At a controlled airport, ATC tells the pilot which runway to taxi to, and I just can't see a scenario where the controller would tell the pilot to taxi to runway 26 full length, much less a 26 intersection. I would be very interested to hear the ATC tape on this one...
Also, flow contol to ATL begins at 6:00am EDT 24/7/365 (at least for TOL...I have to assume LEX is the same way), so the tower would have needed to acquire a departure release time from Indianapolis Center's Traffic Management Unit for this flight, and I don't think they would be trying to beat the rush at all. Plus, I have to doubt LEX would have any other traffic (besides maybe one other plane or so) at 6 in the morning on a Sunday, where the controller would have to "shoot a gap".
The fact is it won't be hard at all for the investigators to determine the runway that was used. ATC tapes and the flight data recorder will tell the story. The runway theory will be confirmed or denied relatively shortly.