60Da fills a niche they haven't had a product in for about SEVEN years already. It's their best choice of body to adapt to this purpose, too, IMO. Avid astro's have likely worn out their 20Da a few times over by now. Also nice to have more res to catch those little dots of light.
I doubt they sell many of them, might almost fit on the "good will" list to produce such a product.
Still, altho 60D has one of the better levels of per-pixel noise in the Canon group of products, I wonder what tweaks it may have in it to help reduce noise even more?