The signs don't appear to be good for running SL on a Mac purchased today or in the future. So far, everyone who is doing that is using a 2011, correct?
Not sure I totally understand the question - FWIW I'm running 10.6 on a 2010 Mac Pro and some older machines.
Also, while there may exist some 2011 Macs that can run 10.6, that does not mean all 2011 Macs will.
If buying a new Mac, you will probably want to run a current OS on it.