I wanted to chime in and let you guys know that there is hope out there . . .
I had very little intention of replacing my two MkII's earlier this year when the M3's came out but, of course, I was curious and open to picking one up if the opportunity arose. I wasn't going to pre-order one and wait for some unknown amount of time but one day I was texting another forum buddy about something Impact related and he let me know his local dealer (Penchetta Pen & Knife) had just received a couple of M3's. After a quick call, I got a 0.22 600mm sent out that day and received later that week.
A couple of weeks later, I put up a WTB ad for an M3 in the Classifieds and another member P/M'ed me to tell me that Baker Airguns had a couple of them in stock. Another call there resulted in a 0.25 500mm M3 being delivered the following week. In both cases, it was the first time that I'd purchased from either of these dealers but both provided a first class experience and I was very happy.
I guess the moral of the story is: if you're not dead set on dealing with one specific vendor, these M3's do show up from time to time. So depending on how quickly/badly you want one, you can either put your money down and wait or search more actively on a daily/weekly basis and improve your chances of getting one sooner.