I wouldn't expect it to work with so many, but I noticed when experimenting with SNMP that there are 256 registers for storing associated MAC addresses. I have two 350 APs with 25+ clients on each running IOS and the processor usage, memory and traffic stats all look fine. I have had a problem with IOS crashing (dot11 down, eth0 down) intermittently, but it doesn't seem to me that it is a problem with the number of clients or the amount of traffic generated.
