I have a couple Neato botvacs, one of the older models runs downstairs with the pins, model is a D80 I think. It does just fine, though I only have 3 machines for it to deal with.

I don't know how many others have similar functionality, but the Neatos actually have a laser or similar optical mapping hardware and map out the area and clean in an orderly grid/don't just bump into everything constantly spiraling around. I like them, quite happy with mine.

Though they are D-shaped with a "squared front", maybe that is what you're already tried...