I thought DPMS was manufacturing AR-A1 rebuilds now? Saw a few at a gunshow last year.. mostly mil surplus A1 (or A2, your pick) parts on a new receiver. A little receiver slop, obviously worn but well refinished stocks... $699 as I recall.
And I know Bushy still produces A1 upper receivers.. have they released that lightwwight barrel yet? Might be possible to get what you want built new from them... postban config, of course.
-K