I think if the DBSO DCC/lights version was heading above £80 that I doubt it'll be produced, with the additional cost left to the buyer to fit themselves if they want it.
The autocoach is an expensive example, but I would really have thought there would be more economies of scale from the Mk2fs in general. £60 each would be expensive, but if it gets much higher it will greatly reduce the number of people upgrading their fleets from Airfix/Mainline/Dapol/Hornby/Lima versions of the air-con Mk2s