Samuel Fila Yes i agree it is a marketing tactic, that why I mentioned "assigned" condo project. Since the OP is looking to purchase a condo and long term stay, it may just fit in to what's he's looking at. Just have a look anytime ^_^
Deanna Lynn Denis has a good suggestion about the ED (Education) visa. Since both of you will be here for the long term, it will good to pick up the Thai language and learn about the culture. You will enjoy your stay more and meet new people in classes.
Check out the "Free Visa" option on the website. U can get a Thailand Elite Visa for Free if U purchase a condo under the assigned condo project. This may work out for U.
has suggested, the Thailand Elite is the best bet for both of you for long term stay. Check out the link that I attached earlier. As what it says on the Thailand Elite website "This Is The Ultimate" ^_^
Your wife is a Chinese citizen so it will be best for both of you to check with the Thai Embassy in China on Chinese citizen travel to Thailand. China citizens and some nationalities have certain restrictions applied by the Thai Immigration so make it your 1st priority to confirm this before proceeding any further.
U and your wife can apply for a single entry 60 days tourist visa each which can be further extended by another 30 days at Thai Immigration when both of U are near the end of the 60 days, Thereafter U can take a short trip to nearby country like Laos or Malaysia which gives U another 30 days (for flights in/out of Thailand).