Well, not really, I guess it's because I have been doing it lots of times in PT I miss the function in RB :-)
By the way, I just got a similar answer from PG:

"When you merge the mono tracks, you'll see the merged track is a stereo
track but the L/R tracks are MONO. So in order to get a mono track out of
it:
[ Track > Split a stereo track into 2 mono tracks ]
Delete one of the mono tracks, and the stereo track

That should do it. Let us know if that doesn't work for you."

I consider it a work around and am sure that it will be remedied in future releases. Don't get me wrong, I'm really satisfied and content with RB, I had just gotten so used and delighted with PT that I compare everything to that :-)