Have you tried talking to the big shops that deal in IFS components, like FatMan, TCI, Heidts, Morrison, Kugel, etc? Like Dave mentioned, I'm not sure that anyone reputable is going to build you A-arms without seeing the integrated design to be sure the geometry works, and reviewing and analyzing your custom layout likely wouldn't be free. It may be that if you give them your basic dimensions of track, wheelbase, and steering angles they can package something from parts they build normally?