[r691175002]

Ether is correct that I will need some kind of feedback in this application. Most of the motion will be at very slow speeds or completely stopped and there will be a lot of reversals. The motors will also be fighting a lot of torque. Unfortunately most hobby controllers won't even let you reverse, so accurate positioning is out of the question.

There are a few reasons that I want to avoid off-the shelf sensored motors:
Because of their applications, they tend to be more expensive, heavier and harder to find than hobby motors. They are also mostly inrunners and I really want to avoid having to gear down 60k rpm four times.

I have no problem attaching an encoder to the back of a sensorless motor to get feedback.

I still find it weird that it is so hard to find something that will work. Closed loop brushed controllers practically grow on trees - brushless motors aren't that unusual...