The only option I can think of that could work is if the new mortgage were no more than 97% of the current appraised value. That would trigger PMI assuming the loan was more than 80% of the value - but there is a way to prepay PMI in full so that there is no monthy payment.
You can't do another HARP but you potentially could subordinate the 2nd to a new first mortgage - however only if the combination of the two did not go over 95% of the new value. If you have any cash to make up the difference that could help you, or some 401k and insurance policies have loan features you could use to pay some portion of any gap.
FYI - 30 year fixed rate today with 0 points or origination fee would probably be at about 3.5%. I can lend in TX (headquarters is in Dallas) and would be pleased to show you some options.