Best of luck to you!
Sometimes sellers ask me about renting a negative equity property, and moving to yet another home.
It is sometimes possible, but the net might be tough to justify. i.e. you may lose even with doing a lot of smoke and mirrors.
Banks are not too keen on that. You need good "one on one" advice, since as you have heard, the interest rates for investment properties are not as good as for your primary residence.
Give an agent a call with your ideas. Good ones have seen it all and suggest proper directions.