Yea well first with the water piping, you will either have to buy your own water heater, or connect in with your existing one, which is easy, and the cheaper way out. If you have a basement or crawlspace you will find the water pipes, and you wont have to go through foundation, there are ways out beside going through concrete!
Cord wood sounds like it would work, but are you doing the whole house cord wood or just the foundation, a foundation on bedrock would have to have some concrete due to shifting of the bedrock. As long as you have concrete reinforced with rebar you should be okay, and then start with the cord wood, but you might be able to do cord wood foundation for a while. By the way I think cord wood is beautiful!
Another thing, I know you said you wanted an insulated foundation, but how about you raise it slightly about 6 inches, and put large posts beneath it, you can do that with a rock bit in an auger, and you can still get great insulating qualities that way. You seal the bottom with brick, and use a lot of insulation under the floor. And if it will be 12x6 the house will be very stable still.
What ever you do I hope you have good luck, and keep in mind mobile homes have very little insulation if that is the way you choose.
I hope I have answered your question, and keep in mind I am no contractor I just turned 15 y/o but I have been building and framing for several years, and I hardly know anything! Good Luck!