Building an Ada compiler

[erkodjk@aol.com (ErkoDJK)]

Some friends and I have a crazy idea.  We want to build an Ada 95 compiler
targeted for the Macintosh computer (without requiring Unix, like
GNAT/GCC).  To that end, I would like to ask the Ada and compiler experts
here (and anyone else who wishes to respond) for some information,
including, just how insane are we?

Self-effacing humor aside, just how big a project is an Ada 95 compiler? 
Those of us planning to work on this project are all Ada software
engineers with at least seven years of experience, but none of us are
compiler experts.  I am a pessimist, and feel that the project size
estimates my friends have come up with are low.  Historical data from
other projects would be helpful.

What sources are available to help such an endeavor (other then the AdaIC,
and Apple)?

How much interest is there for an Ada 95 compiler for the Macintosh that
does not require Unix (It will initially work under E.T.O., the MPW
replacement)?  This seems to be a neglected market.  The GNAT-Mac project
(which requires MachTen, a well-regarded Unix), and the outdated Meridian
Ada compiler (now in Rational's hands), are the only Macintosh Ada
compilers I am aware of.

Thank you for your help,
David