I don't remember all the technical details now, but from what I recall Phase was testing said device but when Apple released OS X 10.5.4 they completely rewrote some part of the code that basically made the wireless adaptor incompatible.
I haven't heard anything about it in months, so I don't know if it's still DOA, or perhaps going to be re-introduced with the new backs this fall (or at Photokina or whenever Phase finally intro's the new stuff).