Do a spreadsheet and you might see differently in regards to savings on gas prices vs. payments.
Add in depreciation, taxes regustration and insurance and I don't see it penciling out.
There's no way you can get double the gas mileage and justify the expense in purchase and depreciation. The gas mileage argument has allowed many a man to scratch his new vehicle "itch" but I have to agree on this. It ain't gonna be a good move.