I put this on the back burner for a while, but finally got back to it. I found a solution that works for us by simply calling the pbuilder in a script first, rearranging resulting files, and then building the DigiESP generated makefile in release/makefile (using cygwin420/bin/make). You don't need to use the "Digi 7.5 Build Environment" bash shell, a normal command prompt shell will work provided Digi and cygwin are in your path. This does mean checking the Eclipse generated "release/makefile" system into your VCS (we use SVN), but this is not a huge deal. If anyone needs it, I can post our script.