LOL Chris - just my warped mind going on overtime but when I read that sentence of yours with the word "reliant", I had this vision of Top Gear's "shuttle" being recommissioned to service the ISS.
Nasa do not but ESA do. The european space truck or 'ATV' can carry a payload of 10 tonnes to the Orbiting space station automatically. I believe this is more than the shuttle can carry.
Johnnyboy ..you are absolutely correct, I must check my sources in future. According to wiki the normal shuttle payload is up to 22.7 tonnes but it can be increased.