BTC-e would have to become a ripple gateway like Bitstamp before you could do that.
Can't a series of users themselves become a gateway?
I thought ripples main selling point was finding routes?
Problem is providing trust along those routes.
Why not just do the same thing the exchanges are doing?
Make the other person provide a deposit and THEN, issue the IOU.
Sounds like a solution? (At least until a proper gateway is implemented)