Mark,
Not cheap or close, Mitch Piper (Piper Motorsports, in Sterling, VA) will get your seat low enough to get you on the track. To fit my 6', 5-1/5" into my sunroof 86 Carrera, we cut out the sunroof (add 2"), got a Kirkey seat (add another 2+ inches c/w stock seat), cut out seat rails for mounting to the floor (added about 1") and put in Sparco rails (removed about 3/4"). My vision line is now right in the middle (up to down) through the windshield, and I have INCHES above my head with the helmet on.
A hair closer would be Mike Levitas (TPC) in Jessup, MD, and he could probably do the same thing (except for removing the sun roof). Even closer would be Trak Ratt
.
Peter