Well you said flash suppressor and the only one I see right off is the Yankee Hill Machine Wraith quick disconnect flash hider. At $70 apiece I'm not sure its exactly what you are looking for. If you want a muzzle brake in that thread size and pitch the Harrell brothers may be able to make you one up that will suit you.
http://www.harrellsprec.com/
edited: I saw your post on the other board and ftf industries does offer attachments as well as kyimports. You can never search the internet too much