If you're looking for a similar sized tractor, it's gonna be almost impossible to find a gas engine, that I know of new. A bit smaller option, with gas and 4x4, would be the simplicity legacy xl. A good non 4x4 option would be the cub cadet xt2 gx54d. The d means it has rear differential lock, and can be purchased new for 4300, plus the cost of a blower and weight kit. The cub is less than half the cost of the simplicity. Another option is the cub xt3 gsx, which also has a locking rear diff. This machine bridges the gap between the xt2 and simplicity legacy xl, both in price and utility. There is a green option, but the build quality of the small attachments doesn't match the price, or competition. I really like the simplicity, but couldn't justify the expense when I bought my cub last year. Those are the biggest gas engine machines that I know of, that are sold new. Used, there are hundreds of different good options.