I haven't. However, a while ago I did a 30-day extension of a visa exempt entry at immigration and I asked about getting a re-entry permit afterwards and was told that I could. In the end I decided not to spend the time to do that and just fly in again visa exempt since my history wasn't excessive.
If you can get to immigration before you fly you might want to see if it's possible to get a re-entry permit off an extension. Or just choose one of the other options, if you have confidence in them, such as using a safe entry company or a land crossing or both.
if you entered using a German passport then you would have entered using visa exemption and not visa on arrival.
You can get a re-entry permit for the entry stamp given for visa exemption.
You need to either do this at your local immigration office or at the airport BEFORE you go through immigration. Once they stamp you out it's too late to get a re-entry permit.
If you are going to do it at the airport search this forum for posts from people asking where to get a re-entry permit at the airport you are flying out from and then ALLOW EXTRA TIME to get it when you arrive to the airport.
if your last stamp is only 7 days old and you haven't left Thailand yet, then get a re-entry permit before you do leave (you can get it at the airport).
It will allow you to use the reminder of your 60-day stamp, which you should then be able to extend at immigration for another 30 days.
Re-entry permits are available in single and multiple variants. Since you will still be using your February entry stamp, immigration will hopefully not have an issue.
If you do get back in, look into one of the other visa options that are available for your kind of travel, as others have advised. You could also look into them while you are outside Thailand but some can only be applied for in your home country or a country in which you are a resident.
You have had two warnings so you should assume that your card is marked and that you will face additional scrutiny when entering visa exempt (and maybe even with a visa depending on which one you get).
Another option would be to fly to a neighbouring country and enter by land, assuming you haven't done so already. Last time I checked you could enter by land, visa exempt, twice in a calendar year (search the forums because I'm not up on recent conditions at the various land borders).
Finally, you can pay a company to bring you in without immigration problems. This applies both to air travel and land border crossings.
Well, Tod, obviously I think that you should stay as a moderator. However, I also think that the person who has been threatening and harassing you should be gone from this group.
Out of interest, if the money was brought in in cash and declared at customs on the way in, would the declaration form count as proof that the money came from abroad? I'm not actually sure what documentation you get from customs in that situation.
I'm curious. Did your embassy specifically ask for proof of accommodation for your ENTIRE stay in Thailand, when you were looking into getting the tourist visa or did they just ask for proof of accommodation?
Well, you could also just fly out or travel via Cambodia or take a train (or a bus or a coach) to Pakse.
I have no idea about clearing your overstay at any of those land border crossings though. However, you did mention, in a different post, that you could clear the overstay at your local immigration office first (I don't know how that works).
Why don't you apply for the single or multiple entry Non-O visa based on marriage or visiting a Thai family member in Laos?
Why use a tourist visa if you have all the documentation for a Non-O, especially with your history, unless you want to stretch out the time by getting a tourist visa, then a 30-day extension, then a 90-day Non-O in country, then finally an annual extension? Even then getting a single entry 90-day Non-O then a 60 day family extension then moving to an annual extension would do almost the same job.
As I understand it, you don't need proof of funds at the Savannakhet embassy for a Non-O based on marriage or visiting a Thai family member.
You can get a single entry visa for 2,000 baht (which you can stretch to 5 months with a family extension) or a multiple entry visa for 5,000 baht (which you can stretch to 17 months but you'll need to do multiple border bounces and then get a family extension at the end).
With either of these options you can move straight to an annual extension when you are ready. I don't believe that you have to use the full year of the multiple entry visa first unless you want to but someone can correct me if I'm wrong.
There are a number of posts about obtaining this visa from Savannakhet on this forum. Many of then will be tagged accordingly so they should be easy to find if this sounds like the right option for you.