There is a rumour that Comair will be getting additional B737-400's from elsewhere to replace the existing B737-300's. Perhaps B737-436's from BA Mainline? This would not involve any changes to the paint scheme or interior, other than changing the registration from G- to ZS- and would surely keep the BA purists happy! ;-)
I notice that B737-436 G-DOCU has already been withdrawn from the BA fleet and has been sent to Victorville for storage.