In addition to those already mentioned, I can personally recommend Bluebird Haven (
http://www.bluebirdhavenirisga...), Blue J (
http://www.bluejiris.com), and Matthews (no website). There are several lists of historic iris sellers floating around, one on the HIPS website. Sadly, quite a few sellers seem to have gone away in the last couple of years, though, and new sources spring up, too, so such lists are usually more or less out of date. The one at
http://www.brightonparkiris.co... is pretty helpful, as it is pretty extensive and also gives a little description for each source.
Good luck,
Brett