You don't even need to go that far out (.tel, .me, .xxx or even .co), look at what happened to the equally hyped .biz (
"the extension that means you're really in business" as they put it... ? lol), .us and even .info.....
The examples of people who've lost $100,000+ that I've read about are in the .mobi extension, some lost a lot with .co but more experienced domainers knew better by July 2010, plus the prereg fee for .co was high, noobs got burned there
Thank God I never went for .tel, .me, .xxx (this one is way too expensive as are .adult, .porn, .sex), .ws, .name, etc. And even for .biz and .us I did not spend that much when those 2 were much more mainstream, I did for .info (maybe it'll come back one day, after I've dropped all my .info names of course...)
while .mobi was really hyped to death, let's not forget that other TLDs were hyped heavily as well, even after the demise of .mobi. Some people again lost five or six figures in .tel .me .co .xxx etc. History always repeats itself. Different players, same game.