Typical companies that make AC compressors for the OEM's these days are Denso and Delphi. There may be others but those are the biggest ones. I actually design these parts and their mounting on the engine. How much extra room are you looking for? I ask because often times the AC Compressor size doesn't change a whole lot externally with lower output or aftermarket stuff but rather the differences are internal usually. Another option is to run an electric AC compressor and mount it wherever you have room then put an AC delete pulley where the old compressor used to be.