Just for archival's sake.. the quietest keyboards I've used are from Zippy. Look at their slim line series which uses the same material in laptop keyboards which are quiet to begin with.
I've been using the WK-801 for half a year now and just purchased a WK-711, both pretty much silent compared to my Dell Quietkey (yea right) and $135 Cherry quiet keyboard. Search for Zippy keyboard at Newegg and see what they got.
They also make sexy aluminum keyboards that still only seem to be available in Asia at this point.
Link. You can probably have one imported if you're ambitious enough.