A good local trans builder can put one together for you, and you probably will not have to pay for shipping. You tell him what you want to do with it, make it as heavy duty as you want. I had a custom trans built for my 454 install. If you supply the core (local P-N-P junk yard about $125-170), it should be about $1400-1500, and a $500 custom 2400 rpm stall torque converter from Circle D (special deal on right now) will handle anything your LT1 can throw at it. I installed it myself, and saved a few hundred dollars (I put the engine and trans in as a unit). It is actually easier to pull both, and separate them outside of the car, then join the new trans to the engine, and install it as a unit. You are still a young guy, and should be able to do it single handed. I swapped an engine last March by myself, and I am over 70.
When removing the engine/trans unit, cap the back of the trans or you will have an ocean of trans fluid under the car.