I would think that would be a perfect motor. If you could find a smaller pinion, it would slow down the head speed. Isn't a pinion easier to get than a whole new motor?

EDIT:

Here you go: http://www.allerc.com/product_info.php?products_id=1487

10 tooth, 2.3 mm, 64 pitch, brass pinion...
They're on backorder, but what the hey.