just got a response in the tips and tricks forum that somewhat addresses this, though, not in the best way:
https://forum.cockos.com/showthread.php?t=222760
apparently i can edit the S&M.ini file to get more than the default 4 region selection actions. that's helpful but it would still be much better to be able to make an action that selects a region by name. is that really not possible?
thanks,
babag