are you 100% sure or going of something you read, do you know someone who arrived today after 4pm that actually has there passport stamped for 60 days visa exempt?
Yes 30 day exempt than 30 day extension at kamphaeng phet immigration office had till 2nd july but left on the 26th, got pulled up at Suvarnabhumi Airport, had to go to side counter and show receipt, but had 2 receipts 1 for extension and 1 for fine for not notification of residency, not really sure which one they were interested in , but stamped passport and left no problem.
You don't require anything for that amount of time , on arrival you will be given 30 days visa exemption, nothing is required just turn up with your passport.
The 30 day extension is 1900 baht on its own , just go to the nearest immigration office, every province has one, they do speak English. You will need a passport size photo, just like your passport and a photo copy of your passport its just a single form you fill out, it really is easy and simple. You will spend more time with an agent then it will take at the immigration office
If your getting the 30 day exempt into thailand than crossing by land to another country and coming back into thailand by land you can only do this 2 times in a 12 month period but fly in and out as often as you want, until you get a unhappy immigration officer than you might get chastised.