Hey, i didn't know about this challenge existence, couple of things like reaction wheel, batt and antenna is clipped in for aesthetical reasons, and 75*75 instead of 100*100 km orbit in the proof, although it have some deltaV in reserve, so no scoring attempts can be made, but i have pretty capable craft right here: Skyranger 4
Test run was made with 102050 kg of cargo, which is 46% of gross mass, with efficiency of 86 funds per 1 ton of cargo to LKO.