I interviewed loads of lifecoaches for a tv programme once, and thought that, while I did meet a couple of charistmatic and interesting people, the majority of it was a kind of pyramid selling scheme for the middle classes, who were all coaching each other and paying each other for the priviledge.
But - and tell me if I am wrong here - it may not be the right thing for you. Life coaching seems to me to work best with people who are 'stuck' - who want to go and do something different but lack the confidence or the knowledge of how to get there (90% of life coaching seems to be about breaking tasks down into small, manageable steps and then telling you to do them).
But you seem to be in potentially a much more interesting position (and to tell the truth, one that I am rather envious of). You have money coming in, a world of opportunity, but nothing is particularly grabbing you at the moment. For what it's worth, my free life coaching advice would be a) take some time off, because you will not know what you want until you get off the treadmill and b) play - have a go at all sorts of fun things, perhaps do some volunteering around stuff that interests you, but don't feel that any decision you take has to be the absolute one. Then you will at some point find something that really engages you and you can get on with it.
What also might be good are the kind of courses which are about finding out what you really want to do - a friend of mine did Passport, which is a weekend thing. I know there are others - perhaps someone else knows them?