The Raleigh rack was, IIRC, "inspired by" the Tubus Cargo. Velo Orange has a similar, and less expensive, rack made by Daija. The Axiom Streamliner series is also a Tubus inspired design which seems to offer more mounting flexibility which may make it easier to duplicate the Sojourn rack's geometry on your bike - particularly if you have shorter chain stays.
Note that if you don't have seat stay braze-ons then the Axiom is the only one of these three that will work.