Question #1:
You could purchase from KuSat.com. This would get you the receiver and the dish, minus the installation. They will set up with a new account.
You can also purchse dishes on Ebay or similar sites.
Do not count on purchasing a dish in Arizona, at a garage sale, etc. I tried this route for several years and was unsuccessful. There are no retail outlets that I could find in Phoenix that had the dish available.
You could also contact "Ask Jim" at Shaw and tell them your situation. They will likely require you to sign up for the Home Away From Home Program (HAFH), and it will cost you an extra $100. I once investigated this route, telling them that, as a renter in Quebec, I was not permitted to install the dish at my rent (which was the truth), but wanted to take it "to my cottage" (which is really my permanent residence in Arizona). They didn't have a problem not doing the install in QC, as long as I used the QC address as the service address and as long as I signed up for HAFH. In the end, I did not go this route, as I had no good way to get the dish back to Arizona. Note that this was several years ago, so their rules may have changed by now. But it wouldn't hurt to ask.
Question #2:
What area of the Valley are you planning to move to?
Depending on your answer, there are certain areas of the Valley that receive many Canadian visitors for the winter, e.g., Apach Junction, Sun City. There are installers in those areas who are familiar enough with Shaw to get the job one. I know of one in Glendale who is not particulary "workmanlike", but they were successful in doing a Shaw install for me several years ago. I can send you their name in a PM if you wish. The big hang-up seems to be that most installers in Arizona are familiar with Dish or DirectTV and seem to get hung up on pointing the dish. From practica experience, I can tell you that pointing the dish is not that difficult if you follow a few basic rules. People on this forum can walk you through it if you want to go this route.
The 75e dish is preferable in Arizona, and the signal level is great.