I am not familiar with the specific codes there in Virginia, but it is possible to build a home that is off the grid and that is code compliant.
- Many homes today use propane heat. I don't see an issue with that.
- As for lights, we've been lighting homes with candles and lanterns since the beginning of home construction. I don't think there is anything in the code that prohibits it.
- You may need to install some sort of rainwater catchment system for use in case of a fire but that would be something specific a code review would reveal.
Have you thought about wind power, fuel cells, or biofuel? All are sustainable viable alternatives to grid power as well.
Also, are you positivesolar poweris absolutely ruled out? If you send me the address approximately it is very easy to tell for sure, unless the lot is heavily treed, in which case you are probably right.
For more information:
Read Florian Speier's Q&A "I want to help get my mom's house "off the grid." Where do I start?"