Dan,
While I am not familiar with a 901, the Buck 701 was the largest knife in the now discontinued 700 series of heavy duty pocketknives. I sometimes see one offered on eBay and that may be the best place to locate one. However, I am sure that there are dealers who still have some of these on hand. You might try Dennis Wright. He lurks on this forum and can be emailed if you find one of his posts.
The 700 series knives were shaped somewhat differently than we are used to seeing. Some people really liked them for their stoutness. It would seem, however, that not enough people bought them. The line was first introduced in the 1980 catalog (model 703 Colt) and subsequent models were soon added. So, the series had a run of 20+ years and that is not bad.
Buck will still accept special orders for these knives if the dealer will meet their minimum requirements. I am unsure what the minimums are, but I would guess 250 or 500 units.
The 700 series can be found with birchwood, stag and the most recent "hardwood" inlays. Also, a few special order jigged bone examples were made in the early 90s for Bass Pro Shop and there are probably some other special order inlays which I have forgotten about. (I am submitting this info without benefit of my written research notes.) The earliest models had script tang stamps before block letter stamps were introduced in about 1984-85. Handle
shields were originally script and later block and some of us have collected models which have block tang stamps with script shields and knives with script tang stamps and block letter shields.
I have probably told you more than you really care to know but there may be some 700 series fans out there who will appreciate this info.
