How long to wait for an optimal/good PhD thesis/program, should settle for less exciting topics?
If you know precisely what you want to do, I am impressed---but not as impressed as the person who will want to hire you! Instead of applying for programmes near what you are want, why don't you write to people in the appropriate discipline and sound them out. Funding can often be found for a bright, enthusiastic student. That isn't to say you are likely to get a big grant, a corner office and be left to your own devices. But with the right supervisor you might be able to get support to design your project. 

However you should not really expect things to pan out as you plan them. otherwise it wouldn't be research. 

Finally it is not unusual to have a period of "meh" or "second year blues" as we used to call it. So think very carefully before jumping ship.