Small Launch Packages Criteria

The problem: I have a series of payloads I want to put into LEO...

1. Weight = ~38,000 lb each
2. Base diameter = 15 feet
3. Desired altitude = 115 nmi (more or less)
4. Desired inclination = ? [Destination: Moon]
5. Some payloads may contain cryogenic propellants
6. Some payloads may contain radioactive material
7. Payloads are documented to commercial aircraft standards, not NASA Spec
8. Each subsequent payload has to rendezvous and dock with earlier ones
9. Payloads are unmaned, but eventually need to get a crew up
10. Want to use an existing, proven launch system
11. U.S. launcher is desired, but not a strict requirement

The questions:

1. What's the best launch system to use? (Cost is paramount.)
2. What restrictions does the launch system place on my payload?
   Example: Do I have to live with DPRO? NASA-STD? MIL-SPEC?
3. How much will it cost?
   1. Rocket
   2. Integration of payload with launcher
   3. Launch control and tracking
4. Who makes it? (Where do I write for specifications?)
5. Where do we launch from? Who controls the launch site?
6. Can I save significant cost by redesigning for smaller payloads?