That you know of. Any of them could've bottomed off-camera and there are pleanty more lesser known American gay models who only toped so far. Besides, I once heard somewhere one of the wisest things ever, which is you gotta try to bottom sometimes to know what it's like in order to be a great top and lover, which by your list of only tops mostly checks out.
THERE ARE JUST 9: "VIRGIN" TOPS LEFT IN AMERICAN GAY PORN BUSINESS: 1. IGOR 2. PETO COAST 3. ROCCO STEELE 4. VIKTOR ROM 5. TYLER REED 6. DR. WOLF 7. ARAD WINWIN 8. DIEGO SANS 9. MICHAEL LUCAS.