I didn't build this shuttle for this challenge so it has no payload capability but I though I share it with you guys none the less. Behold, Kerbterprice. The 0.35 all stock US shuttle approximation. Only boosters for lift assist and the main engines run off the big tank only just like on the real thing. It also has enough fuel for the orbital maneuvering engines to get to an space station in low kerbin orbit and de-orbit for an KSC landing.
I got an bigger and even more realistic shuttle that makes use of the ARM parts but so far I have not been able to make it preform well. It gets into orbit but is a real pita to fly and its forced to make use of the on board fuel just to make orbit leaving practically nothing for actual orbital maneuvering.