How to propose/work on a project for work
I think the fact that you're an hourly intern puts you in a tough spot. While I find your spirit and initiative admirable, and probably a sign of a good engineer in development, I think you're unlikely to find a solution where you will get paid to work on those ideas. 

Getting paid to work on, as you say, "pie-in-the-sky" ideas is one of the hardest qualities to find in a job. You need a trusting boss, an impressive track record of successful implementation of previous work, and a company in a dynamic field. I think it's easier to find jobs that are high-paying, easy, or both.

The best strategies I can think of are to impress your boss or inject your ideas into the R&amp;D team. Perhaps you could swing a deal with your boss along the lines of "If I can get this project done well by Monday instead of Tuesday, can I spend Monday working on this new idea? You pay the same amount either way, and this idea is really awesome."?

Good luck.