We currently have "engineered at," "recorded at," "mixed at" and "mastered at" as Place relationship types. I just ran across a release that specifies where it was edited (http://musicbrainz.org/release/cf4d4356-5398-494b-9624-fdc304194425 , relationship found courtesy of http://www.discogs.com/%E9%BB%92%E5%A4%A2-%E8%BF%B7%E3%81%88%E3%82%8B%E7%99%BE%E5%90%88%E9%81%94Romance-Of-Scarlet/release/2224805).