Yes, the idea is not bad. It basically turns your focuser into a SIPS, the FeatherTouch Focuser with the CC in the base of the focuser.
What are the pitfalls?
1) placing the CC lens at the correct place in the optical light cone.
2) getting eyepieces with their focal planes high in the eyepiece close enough to the CC lens to focus without having the focuser drawtube hit the CC lens holder.
3) since this does not parfocalize your eyepieces, the range of focuser movement will likely have to be 1.5" or more.
4) it eliminates the use of barlow lenses, which are typically used below the CC lens.
Let's address each issue.
1) I suppose the same technique for setup used by the Paracorr-in-a-focuser would work, assuming you could put some translucent tape over the focuser 75mm from the lens:
http://starlightinst...nstructions.pdf This wouldn't be too big of a technical hurdle, but you'd need some way of moving the lens in and out relative to the light cone of the scope.
2) Some eyepieces would need to nearly touch the lens to get close enough to focus. So it's possible one would not add any spacers to the lens. You would want the eyepiece to be placed in the focuser drawtube, not any accessory, so it could get as close as the barrel of the eyepiece coming close to hitting the CC lens. Otherwise, those eyepieces with high focal planes would never achieve focus.
3) A typical set of eyepieces that includes some 2" eyepieces will need that much travel, and the drwtube will need to slide past the CC lens and not bottom out on anything past the CC lens in order to get the aforementioned eyepieces close enough to the CC lens to focus.
4) To barlow 2" eyepieces, a barlow is usually placed inside the coma corrector in the light cone, maintaining the coma corrector to eyepiece distance. Mounting the CC lens as envisioned eliminates this possibility. Using the barlow in front of the eyepiece precludes coming to focus in all likelihood.
So what if you used the coma corrector in its own tube, adjusted the spacing for perfect correction for one eyepiece, froze your focuser, and parfocalized all your eyepieces to the one you had adjusted correctly?
--all your eyepieces would be parfocal
--all your eyepieces could/would be adjusted to an optimum coma correction setting.
--barlows could be used
--finding the correct position of the CC in the scope's light cone is easy
--and adjusting a new eyepiece would be as simple as parfocalizing it to all your other eyepieces. If you parfocalize it, the CC doesn't even have to be in place 9though it could be), since parfocalizing is a process of bringing all your eyepieces' focal planes to the same position relative to the focuser.