If you want a frame level then the usual suspects listed above are your best bet. Taylor Hobson also made one, as did a Czech firm whose name escapes me right now. I have one that I like quite well.
In the Starrett 199 style levels can be found on US ebay from Lufkin, B & S and Scherr-Tumico. All of those brands made good levels.
If anyone wanted roll their own you can buy precision vials in housings from Geier Bluhm in Rochester, NY
Finally, I will mention again the rebranding by Hahn & Kolb and other firms. My own Wyler magnetic was sold on ebay as an M & M (I think...I cannot check it right now) Anyway, it was the name of a German precision dealer. Messhur und something or other.
Greg