With the (very) recent release of the VC11 November CTP*, I wonder if there is a way to currently (or plans to support in the near future) get boost build to use the new toolset to play around? The problem is that it's installed side-by-side the RTM compiler (as it's a preview) without a new command prompt environment which correctly sets up the env vars.

This could be worked around, but it can only be done after the env vars have already been set by the VC scripts (as they need to be overridden), as described in the comments on the linked website (quoted here):
The command line compilation can be configured by updating the PATH and INCLUDE variables. After launching the VS2012 Developer Command Prompt, you need to:
set PATH=[drive:][Program Files]\Microsoft Visual C++ Compiler Nov 2012 CTP\bin;%PATH%
set INCLUDE=[drive:][Program Files]\Microsoft Visual C++ Compiler Nov 2012 CTP\include;%INCLUDE%
Everything should work after that.
Hope this helps,
Marian

Is there a way to have Boost.Build set these env vars after the environment has been initialized, or is it 'too late' by then?

Thanks. 

http://blogs.msdn.com/b/vcblog/archive/2012/11/02/visual-c-c-11-and-the-future-of-c.aspx