Well I am looking at this from a manufacturing standpoint.
I don't know that there has been a proper analysis of the boards from a u and a ul to determine if there are any actual hardware differences between them.
HTC would want to manufacture as many devices on a line as possible and if they can make the u and ul on the same line without retooling they would do so.
That's why I am wondering if the radio differences in the u and ul are all in software.
All phones these days have a software defined radio.
The hardware geek in me is curious.
It would be nice if you can turn an AT&T M7 into a T-Mobile M7, etc.
But yes.. it's probably wishful thinking.