A "blind signature" sounds like an odd concept.
What can be done I just thought up is adding another transport layer to bitcoin. And breaking up and distributing the wallet's contents "sum" among strangers into something like a checksum. Then on transactions bringing the chunks of checksum partially back together.
How it's broken down can vary. you have to remember though, if you are buying something for $10 all that needs to be verified is that you have $10 or more for the next step.