Never available from the US? I wouldn't give up on the possibility, as there are lots of routing possibilities.

Thousands of miles needs for awards from Europe-South Africa (Y/C/F)
Air Canada: 70/105/140
United/USAir: 60/75/100
Lufthansa: 60/90/140
ANA: on South African Airways: 55/85/120 [Available only on SA, so departures from only London, Frankfurt, Zurich, Paris]--there are *A mileage-based awards, probably in the 60/90/120 range, depending on routing and US departure location
Asiana: a mileage based system for *A travel, probably in the 80/120/160 range, depending on routing and US departure location

I'd suggest that you visit the forum of those programs you think you'd be interested in--search around for relevant info, ask questions if needed. You might also think about your travel patterns, etc.