The same thing happened to me, although thankfully I wasn't as invested in the promised job as you were. I worked remotely for a startup for 3 months. It was a well-paid programming internship, and the plan was for me to relocate and come on full-time at the end of the internship.

Three months into the internship, the founders scheduled individual meetings with every employee. They told they were letting me go, and that it was because the company was "going in another direction" or some such. I and another intern were being terminated, supposedly based on seniority.

The technical cofounder said it wasn't at all related to my performance, and even wrote me a great letter of recommendation that helped me get a job. And yet, a few weeks later, this startup had programmer job openings posted on its website. I heard later a rumor that they had basically run out of money, but I don't really know the whole story.

That was my first experience with a startup (after spending a lot of time here and becoming enamored with startup culture), and I must say it almost discouraged me from joining a startup. Luckily, I still kept looking, because I'm quite satisfied with where I ended up.