thought to just post the answer, as I have already found it, for anyone else who might want to know.
Q. How many devices can the Workgroup Bridge support?
A. The Workgroup Bridge supports up to eight MAC addresses on the wired Ethernet segment. But, when a 1200 series access point works as a Workgroup Bridge, it can handle up to 254 clients on the Ethernet side, while it presumes that no other wireless clients are associated to the root bridge/AP to which this AP in WGB mode is associated.
But, keep in mind that when the AP acts in a WGB mode, the AP takes on the association at the client level, which means it is not a true bridge. So it is always advisable to limit the users to a small or reasonable number.
Cisco Aironet Workgroup Bridge FAQ
http://www.cisco.com/en/US/products/hw/wireless/ps441/products_qanda_item09186a0080094644.shtml#q17
