i'm pretty much in the smae position, there's loads of things i'd like to do but trying to formalise this into a pesearch topic is a nightmare.
I've gone down the other route a few times (graduated 2003)and had 4 interviews for different PhDs and been unsuccessful everytime, mainly i think cos i wasn't passionate enough about the topic, especially as I'm quite reticent anyway.
hope you come up with something, what area/subject do you want to study?