Answers to previous unanswered questions:
Plot sizes are flexible to the purchasers needs and dependent on style of house reqired.
Rather than a conventional 'village' style set up the available land is being offered so that each lot is completely individual with access gained via a private road serving no more than I would expect 4 properties.
Regarding ownership, its true that whilst foreigners cannot own land in Thailand there are ways of legally protecting yourself be it by Usafruct or by a lease style agreements. More info can be found here:
http://www.udonpropertyandland.com/?q=node/6Best Regards
Gareth