Not in my area, from what I've seen. It's a shame, too, I think a mech league would be a blast.
Now, for one season in PSP, the ROF cap was 10 bps for everyone except the top one or two tiers, which were capped at 12. There was a provision added to the rulebook which allowed for pure (non-RT) mechanical guns to run without being policed for ROF. I thought this was a brilliant move that could have brought mechanical guns back to the big leagues, but moving everyone to 12.5 bps kind of shot that in the tail. There is now a note for the Masters Division that lets players under 40 play if running mechanical guns. I believe the "younger" player can then be between 30-39. Someone please correct me if I'm remembering wrong. I'm only a couple years from Masters qualification anyway, and the memory ain't what it used to be.
The sad bottom line is that since the industry has a goodly amount of influence over the leagues, and/or the players who play in and operate the leagues, I believe we are unlikely to see mechanical divisions any time soon.