I was also looking for something like that a while back. I think Kubota's 1880 is the smallest modern scut out there. They're still bigger in size compared to the old Case 400 or 600 series (and their Ingersoll versions). But the problem with buying old case/ingersoll tractors (they're great, btw), they're old....you're going to be doing maintenance on them, like regularly. It's also older tech, they have a shuttle shift instead of forward/reverse pedals, for instance. No 4wd generally, although I think Ingersoll did have one model with 4wd. I dunno if any of them had power steering either, maybe that 4wd version did. Those loaders are not quick detach either, at least not as easy to take off like on a modern scut.
As was mentioned by Oldnslo, another option is to just add a Johnny Bucket on your garden tractor. That thing actually is quick detach, so that's handy. But to be clear, it's not a loader, you can't raise it much higher than maybe a foot or so. It's billed as a scoop, but I could see it being an ok option for scooping mulch, hauling it to your beds, that sort of thing. I had the manual version of something like that mounted on my craftsman gt. I only used it a few times, didn't find it all that great.
I have a massey gc1710, absolutely love that thing. With the loader and hoe off, it's only slightly bigger than my craftsman. But then on it I have 4wd, power steering, side by side pedals (I love that compared to treadle), and the mower on it is an absolute beast. If I let my lawn/yard get wild, I don't even bother with the craftsman...the massey will chew right through tall grass where my craftsman would get bogged down.