Just me, but I think you are trying to take on too much leverage. At a minimum, you should probably have 10-20% of your total debt in unencumbered liquid assets (cash, stocks, bonds, etc), and a ELOC is not liquidity.
If your real estate market continues up you would probably kick yourself for taking my advice, but just remember, leverage cuts both ways. Right now, all it would take to put you out of business is a layoff and some vacancy. Hold off a bit, build your liquidity, and save up a proper down payment.
If you are planning to stay in your primary residence for 5+ years a straight refi would probably be worth it.