Just wanted to chime in here. I do know that GSG manufactures the SIG 1911-22 pistol. It is exactly the same as the GSG version except for the SIG identifiers and maybe the grips. I think the Mosquito has been around much longer than the GSG 1911 so I wouldn't count on GSG making the Mosquito.
**Should mention that adding a buttstock or adding a foregrip to a firearm classified as a pistol makes it a rifle. Very illegal (think FELONY) if you do not have the proper paperwork and tax stamp for it. Do a quick Google search on legally converting a pistol to a rifle. Seems simple and easy to convert on your own, but can land you serious jail time if you don't go about it the right way.
Those of you who have replaced the factory crane stock with something else - any interested in selling your factory HK stock? shoot me an email - sahlomonic@gmail.com and we'll talk.