>>I'd like to invest a fixed amount today and get a fixed amount out in 5 years to pay off the mortgage. I'd like to earn around 5 to 7%, but not be taxed during the 5 years I will hold the investment. In addition, I want the gain on the investment to be taxed at long term capital gain rates when I cash out the investment in 5 years.<<

If I understand correctly, you want a 5-7% return, tax deferred at cap gain rates, and no market risk to your principal.

Sounds like investment nirvana. Let us know when you find it, others might like to participate.