Lung Paul speaks the truth. If your 60-day entry expires on 29-July a 30-day extension will get you until 28-August, not more. At this point the first entry on your dual-entry tourist visa is well and truly used up. Flying out 4-Sep would be a 6-day overstay (3000 baht fine). You have a dual-entry visa but still need to physically leave and re-enter Thailand to activate the 2nd entry.

yeah i understand what you are saying... and i figured as much with regard to not getting more time... in my rush to apply for the visa before leaving to come to thailand i had to buy a departure ticket and i did it a little more hastily than i would have liked and just recently when looking over everything realized the timing was a bit off...
as capital_bob says i do have a double entry, but that was part of the reason why i was hoping to get a few more days on the extension (more so than the 30) because i would rather not activate my second entry just to come back and take a flight out of the country again...
that kind of leads me to my next questions... is it possible to cross the border on the 27th or so of august and then re enter on the 28 or 29th but just enter on a visa exemption stamp and NOT activate the second entry?
my last option would just be to eat the plane ticket (again i only bought it because of visa requirements but i figure why not use it if i have it anyway) and just continue traveling through other SE countries and then come back to thailand when i am ready to use the second entry...

is it possible to cross the border on the 27th or so of august and then re enter on the 28 or 29th but just enter on a visa exemption stamp and NOT activate the second entry?
If you choose, once you've entered the other country, you can do an immediate u-turn and exit that country and return to Thailand. Whether you do that or come back 1, 2, 3 days later, or whenever, the entry requirements are identical.
You can ASK the Immigration officer NOT to activate your TV and just give you a 15 day entry stamp instead, but be aware that he is under no obligation to follow your request. Some will, some will not. If he decides to overstamp your TV then there's nothing you can do about that - it's why I suggest that people don't plan like this but get another TV from a neighbour country just before you need to use it.
Clever people are those who buy the airline ticket to show proof of onward travel with a view to USING it rather than just getting it for the sake of getting a visa-exempt 30 day stamp. It's not hard to plan the flight as part of the itinerary.
As somebody said above, you can't just make up the rules to suit yourself. The official at border entry is entitled to assume you got the TV for the purpose of entering Thailand. If he understands WHY you'd prefer to enter instead on a visa-free stamp then he MAY go along with it. If he doesn't, you have no cause for complaint - you'll just need to buy another TV for next entry if you want more than the 15/30 days allowed by a land/air exempt entry.

Hi everyone.
I'm a japanese university student newbie. We can see Mt.Fuji from our campus.
Thank you for this forum.It's very cool. Members comments are helpful. I have a comment and question. If you could wake up tommorow morning anywhere in the world where would it be. and what would you be looking at when you wake?
Thank you. "matane"
I would want to go back to Argentina I've only been there once and it's my favourite place in the world. People are chill and friendly, the city runs at a decent pace of life (unlike Asia), the city has charisma and the food is amazing.
I could walk forever down the streets of BA.
is it possible to cross the border on the 27th or so of august and then re enter on the 28 or 29th but just enter on a visa exemption stamp and NOT activate the second entry?
I've done something like this at the airport. I asked the officer to let me enter on a visa exemption stamp and not activate my 2-month tourist visa. Told him that I was only in Thailand for a couple of days, was going to Malaysia for a wedding, then coming back to Thailand overland and wanted to use my visa then. No questions asked.

Entering Thailand overland, if I show proof of a flight out and back home from Phnom Penh within 15 days, is that counted as proof of intent to depart from Thailand within 15 days? Or do I need to book a flight from Bangkok and change that fight later?

Entering overland you don't need proof of anything except your identity, assuming you're on the long list of countries that qualifies for visa exemption. Present your passport and you'll get a 15 day entry stamp. Simple.
A ticket out of Phnom Penh does not meet the requirements for Thai immigration. However, the chances of being asked about an onward ticket are extremely slim.

The problem is when flying to Thailand from outside the Asia region airline check in staff may refuse boarding if you have no visa or air ticket out for Thailand . However an air ticket from Phom Penh to home country would probably be accepted even though the rules say it supposed to be from Thailand . There is no guarantee but even in countries where staff are strict like Australia they have been known to accept tickets back to home country from another country in SEA. The logic being it shows you are commited to leaving Thailand to get that flight home from another country.