Roy isn't going to be traded. Period. So we can lay that thought to bed. And, if after the new CBA is in place and a hard cap exists (as many speculate it will be), his expiring contract in year 5 won't be attractive either. Unless he retires, we need to get used to having his ill gotten salary around our necks. Hopefully it won't become a 5 year noose. As to Yao being traded, can't say as I blame Houston. When healthy he can be a real asset.
(Didn't read the link yet) Yao is an expiring contract right? If so, then you can forget about it. Yao has value in that circumstance, Roy has extreme negative value (aka: "he's a liability").
Sending Roy where? Do you mean to the Rockets? Not a chance in hell they trade for Roy. Yao is a partially insured, ending contract. We can't trade Roy for that. Roy is not currently tradeable for a price you wouldn't conisder insanely high.