I finally got around to looking at some data I pulled from Seatcounter late last year to look for award availability. I looked at a few hundred flight-days on some routes (looking out across much of 2008). Here were a few, fyi. XC is the total number of award business seats available on the route over the number of days listed.

Flight Route Days XC
UA803 IAD-NRT 246 1
UA843 ORD-GRU 251 241
UA906 ORD-MUC 211 31
UA839 SFO-SYD 239 0
UA914 IAD-CDG 246 173