Ive seen a few Pros GMs now and they are all very big (40+ edges, full profile and very thick shoulders), so they can make them I have just never seen a big GM in a shop or with a normal punter.
I did see however on an old GCCC youtube video that they stocked the Maestro which looked pretty big.
I would've though over the last couple of years they would've done very well selling a "larger" sized model.
All they need is a Chris Lynn type to use a GM Lynn player edition last couple of years and then sit back and collect peoples money.