Correct. It's the motoring organisation in the host country who issues the IDP, and in the majority of cases it can only be obtained while physically in the country. Australians can apply online from overseas and the IDP will be mailed by express to anywhere in the world. However, the cost of this service is about $50 in addition to the actual fee of the permit. Only valid for 12 months
It's probably one of those fake "international licences" you can buy off the internet. It might fool the Cops but it won't fool the insurance company when you have an accident!
As Brandon has indicated, ask yourself "when does a tourist cease to be a tourist?". Thai immigration are a suspicious bunch, and they will naturally assume you are working in Thailand on successive tourist visas, especially if the duration between border hops is very short (some people just go to, for example, Nong Kai, step into Laos, get the entry and exit stamps, and then walk back into Thailand). They will almost certainly question two successive METVs if this process is observed.
You do a border bounce at 364 days (or thereabouts) to get the second "free" year (costs nothing). The beauty of the OA (for those who wish to visit their home country every, say 18-24 months) is there is no requirement to transfer money into a Thai bank account. This is great for people like me who are earning 7.5% (tax free) in Superannuation funds. It's all about individual situations of course.
You're mistaken. The non-O is available from embassies and consulates. It differs from the OA in that it is valid only 90 days, whereas the OA can be pushed out to two years without the need for an extension. The O must be extended within the 90 days, which requires 800,000 baht to be transferred into a Thai bank account