I paid $5,000 for my Honda 40, with electric trim and tilt 5 years ago... and tiller. The 50 is the same engine.
This is THE best time to buy a motor, both used and new. I'll bet you'll find one at a great price. I'm not trying to push Honda just because I have one and because it has worked flawlessly for 5 years... But it will take a tiller, I just am not sure about the other brands re tiller attachment.
I noticed that you live in Portland, I work in Old Saybrook. If you do buy a Honda 50 and you add a tiller on your own, I have the Honda shop manual, you are welcome to borrow it, and, or I can show you how to do it. It's literally plug and play from a wiring perspective (ingenious actually) and the mechanical attachment is really easy. They haven't changed the overall design for many years (I'm not sure about the internal engine components).
FYI... my Honda and my partner's Honda both start well in cold weather... Honda used to have a bad reputation for cold weather starting about 10 + years ago.
Good luck.
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