Seems like an awful lot of work to solve a problem that's easily handled with an external USB or FireWire enclosure. Even eSATA has a max cable length of 2m. That ought to be plenty for most applications. I don't mean to discourage experimentation by any means, but I don't think you're going to save any money or anything doing it this way. Particularly when you factor in all the time you'll spend trying to fabricate such a thing.
Anyhow, good luck!
Never Give Up. Never Surrender.