Very soon there might be no requirements, just buy ticket and go. If your not set to travel for another 3 months or more, keep watching this group for updates.
it's called a TM 30, it registers your place of residence with the Thai govt. Legally, wherever a foreigner stays is obligated to inform the govt within 24 hours, so they can keep track of foreigners. Practically, the only time you need it is if you go to immigration asking for something like an extension of stay.
If you really want to buy land in Thailand, first stop before even finding the land is a good Thai lawyers office. They will guide you through the process, and make sure you don't get scammed. Only can buy land through setting up a Thai corporation, lawyer can do that for you as well.
They're not a bunch of dicks, they're actually very nice and helpful, it's just that the visa rules are so tough they have no choice but to deny most visas.