I'd rent and put the $30K/ yr into savings. When the short sale comes off your credit, you'll have a substantial downpayment.
You don't mention the balance, but the current rate you're paying is 3% too high. Even if you get the rate reduced, you have a $100K issue.
I recommend reading through Will Short Sale Prevent Me From Getting VA Home Loan Later? A bit different question, but it talks more about the short sale. A comment for that question makes a key point - if you have a short sale, will the bank chase you for the balance? If not, you have a choice to make.
Adding note after user11043 commented - First, run the numbers. If you were to pay the $100K off over 7 years, it's $1534/mo extra. Nearly $130K, and even then, you might not be at 80% LTV. I don't know what rents are like in your area, but do the math. First, if the rent is less than the current mortgage+property tax and maintenance, you will immediately have better cash flow each month, and over time, save towards the newer house.
If you feel compelled to work this out and stay put, I'd go to the bank and tell them you'd like them to recast the loan to a new rate. They have more to lose than you do, and there's nothing wrong with a bit of a threat. You can walk away, or they can do what's reasonable, to just fix your rate. With a 4% rate, you'd easily attack the principal if you wish. As you commented above, if the bank offers no option, I'd seriously consider the short sale. There's nothing wrong with that option from a moral standpoint, in my opinion. This is not Bedford Falls, and you are not hurting your neighbors. The bank is amoral, if not immoral.