Unfortunately the dot1dTpFdbTable (which contains dot1dTpFdbStatus you mentioned) is completely empty even though there are clients currently associated.
It makes sense to me that the forwarding table for a transparent bridge would contain an entry for each associated client. Maybe this is a bug in the IOS version I'm running: 12.2(8)JA. This is listed as an 'early deployment release' but I've no idea when the next release is due.
The associated clients are all using VLANs so I tried dumping the Q-BRIDGE MIB too but without success.