I'm looking for the same thing. Seemingly, the best option I've found so far is either the Carbonda 696 or 1056. The 1056 geometry is actually slightly more relaxed from a stack/reach perspective, however Adam told me that it was made to be a "faster" bike than the 696. Usually, "faster" means "more aggressive", so I'm not sure how to interpret that.
In any case, I'm also very much looking for a relaxed geometry frame. The best option may be to have a custom frame made from one of the metal manufacturers, though that is a bigger project than simply buying a carbon frame.