The G&P SR-25 and M110 receivers do not have markings designating full-auto, and the function is easily disabled if you demand realism. The Mk11 mod0 has a suppressor, but not an adjustable stock.
Lol, Cerberus beat me to it, can't believe I missed that.
Western Arms made one about a year or two back, out of production though. WGC and Redwolf both have pictures of it, but it is also out of stock at both of them.
I had one of their championship chamber/barrel setups for a WA with comp, it was good build quality, easily on par with SD, better considering SD didn't make that setup actually.
There were a few stock WA's that came with extended inner barrels, the longest being from the silenced Prokillers or the Gigant. While there aren't any extended barrels available on the market you can probably find either an airsoft store or someone with the equipment to make a custom one for you, as it's not that complicated.
It doesn't have a modular plastic lower frame, therefore it is not a 2011. The only defining aspect of a 2011 is that it has a modular design with a plastic lower frame and metal upper frame.