You can sign up for Advanced RV's monthly newsletter which is generally has up-to-date information. I just received mine today and they feature a couple of custom designed Bs. One has a unique back pair of dog kennels. The other was designed for a mobile doctor.
They have gone to compressor refrigerators and explain why. Compressor refrigerators were confirmed here...
The other thing to note is they are building off the 4 cylinder diesel but every B is your choice. I don't know if any other converter has mentioned that. They say figure about 6 months for them to order the Sprinter you specifically want and then to outfit it. That works out to about 90 days to custom order a Sprinter from M-B and then another 90 days to build the B at Advanced RV.