I'm sure this has been asked millions of times, but not sure how to search for this question . . .

I'm currently on my extended 30 day visa, with a few weeks before I need to fly out of Thailand to get my second 60 day tourist visa.

Lets say I leave on day 7 of my 30 day extended visa with a re-entry permit. Can I get my next tourist visa, but return using my re-entry visa, and not actually 'activate' my new tourist visa until the extended visa expires?

I assume it'd need to be stamped . . . but maybe an immigration center in BKK would do it later?

You would be much better off to just wait until current permit to stay runs out and get another tourist visa.

Your plan won't work because you would have to leave the country to start your new tourist visa. Immigration here will not stamp you into the country.

Well actually it'd be much easier for me to do it on the earlier date because of my schedule.

Four years ago I had a tourist visa, but I convinced the airport staff to not use it and instead give me an on arrival visa for 30 days. A month later I flew into Bangkok from a side trip and then used it. I wasn't around long enough, but I could have easily got a legal 90 days without even extending my visa!

You still had to leave the country to use the tourist visa.

You need to check the use by date on your tourist visa if it is more than one entry. Some are only good for 90 days.

You would loose your 2nd entry if it expires.