I don't know what row spacing you are using now, but if you went wit 30" rows, you could probably cut down on the size. And what I'm going to suggest may not be your cup of tea.
I garden with a 2-wheel David Bradley garden tractor. Row spacing is set at 30". I plow, and disk with a small farm tractor, to work the garden, then cultivate, or make hill rows with the 2-wheeler. You may scoff at the idea, but, professional market gardeners from coast to coast are seeing the benefits of using this sized tractor. And many farm up to 5 acres with tractors like these. I've been trying for 5 years to convince a buddy of mine, who raises produce for market, but he too pretty well scoffed at the idea. Last Fall, I happened to be introduced to a Face Book page called "Gardening for Market". Many of these growers farm anywhere from a 1/2 acre, up to 5+ acres this year with this sized tractor, or even smaller. Right now, most seem to think the Planet Jr. tractor is just the ticket. Personally, I'll stick with my David Bradley's.
I sent a link to my buddy, to show him what these folks were accomplishing with these small tractors. And now, it's the latest, greatest thing, according to him, LOL... He did mention one time, that I may have been way ahead of the game.
The overhead is pretty low. I've bought 2 running tractors with an attachment in the last year for under $100.00. But, I have been using the others I have, for over 25 years. Carrying on, from Dad using them since 1954. Implements only take a minute or two to change. Fuel coasts are very minimal. I seriously doubt I use over 5 gallons of gas all summer, on a 100' X100' plot, and that is only 1/5 the size of the original plot, when I was a kid, for the home garden.
The folks growing commercially add what is known as finger weeders to their cultivators, and pretty much eliminates hoeing between most root crops such carrots, onions, etc. Those weeders are a bit pricey for me, for the amount I grow. But, if I was growing in the amounts they are, and selling, it'd be worth it in labor costs for hired help, like they have to hire to hand weed.
I've added just a few pics of the different tractors, and implements I use. I have several ore different one's, where I use the single gang disk to make hill rows for my onions, leeks, etc.
Depending on what part of the country you live in, you can find them pretty reasonable. Some Craigslist, and Ebay listings are just completely outrageous on their prices.
Again, probably not what you are looking for, as many want o ride & guide. But as far as a little workhorse, with little investment, and operating cost, they are hard to beat. Even if you find a non-runner, you can re-power with a HF engine for $100, or less.