Yes- I was denied an extension yesterday at Immigration b/c my land lord wont fillout the TM.30- just total madness; Rock meet hard place (I can't get them to do it- Immigration's response was "move"-)
I lived in Hotels here for 7 years. I prefer Hotels. The monthly rate is 'usually' half the daily rack rate. So 2000bht/nite becomes 1000/nite monthly up front. It sounds like money is no object for you so go with Hotels. Why do you have to commit to 12 months? just find another hotel and do month to month, also ask for 1 month bond.
It's the airlines that are the gatekeepers not Thai immigration. The fact that you're going to get a retirement visa 'means' you don't need a return ticket etc. If its Turkish airlines it should be ok, explain to them you were advised not to get a return b/c you are retiring in Thailand.