@edgecrusher has a 14.5" PWS... @98Z5V has a 13.7" AR-10 build... I have shot both, and can swear by the both of them. The 13.7" is a BEAST.
That being said, I don't know Double Star, so I can't speak on their behalf. If you are interested in building your own, we can definitely help you find the parts. You could always strip the barrel off your GenII and we can have that sonbitch chopped off. It's only be a about $100-$150 to get that thing humming again. Might need an adjustable GB and a new buffer weight??
(I thought you were downsizing, not adding to the stable?)