Honestly, I don't see the pain in waiting at this point. Having the money tied up shouldn't be an issue if you understood the nature of the project when you go in, which a fair few people don't seem to have. The tied-up money is what has been funding some of, if not all of the project. So in essence, although you can't see a final unit right now, you do have something for your money already in the form of prototypes etc. It's always a case of 'I paid, now where is my product' where as it was plain from the beginning (should anything more than a paper-thin investigation of it's design process and origins have been conducted by those interested) that pre-ordering in this case involves a large dose of faith, and the knowledge that the whole project could fail at any point and we may never receive a final unit.
I've been following since the beginning, I couldn't afford to pre-order until this year but I would have gladly paid on day 1 and waited this long with my fingers crossed. This is now the most exciting part because things are moving faster than they have at any other point, and we can see everything coming together, so it would be madness to pull out now!
It's a bit like paying an oyster that's made a promise to form a piece of grit into a pearl for you, to which it estimates a delivery date and provides you a series of updates regarding the formation of layers and it's iridescence. The date slips further away, but a point is reached where it begins the final stages of formation, you decide that you'd rather have your money back than get the pearl in the end because of the principle of the wait you had to endure.
Ok it's probably nothing like that, but I'm at work and I'm bored shitless.