Looking over the obiquious Salvage Cruiser, it seems that there could be even MORE variants for the ship from the basic hull. So here is what I've thought of so far.

1) Commando Salvage Cruiser (SAG). Before the introduction of the BRC, the Salvage Cruiser was the basic "fast" marine ship the Orion Cartels used besides the basic Viking. This ship would eventually be converted to the CVL class when that was introduced in the later years.
Take a basic Salvage Cruiser, convert the Cargo bay to 8xShuttles. Convert the 2xShuttle to Cargo. Convert the rear hull 2xTrac to Barracks. Convert single BTTY to Barracks. Convert the 2xOption mounts to TRANS.
POSSIBLE BUT OTHER SHIPS ARE BETTER.
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2) Heavy Salvage Cruiser (HSA). This was introduced by the Pharoah Cartel in Y175, mirroring the development of the HBR, trying to eek out some additional lifespan over the aging Salvage Cruiser. The large cargo capacity of this design eventually allowed the few that served in Cartel service to be priority transports carrying vital parts for Cartel shipyards for ship construction.
Eventually this class would be the basic hull used for the Salvage Control Ship (SGS) found in R7.
Take the basic SGS. Remove all readyracks and mechlinks. Convert 14xShuttle to 14xCargo. Convert 3xBTTY to 3xShuttle. Convert 3xRepair to 3xBTTY. Convert 3xRepair to 3xLab. Everything else as SGS.
2a, 2b, and 2c) Obviously as Heavy PFT (HPF) and Heavier CVL (HAV?)/CSV (HSV) could be made off this larger hull also.
2d) Possibly an alternative Patrol Carrier (HVP).
POSSIBLE
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SVC HEAVY CRUISER, LONGER HULL, ADD LR Engines, endless variants