I've not seen any good Ha images taken with a C14, but I have seen some spectacular white light images showing incredible detail taken through a C14 with a FULL aperture Baader AstroSolar safety film filter mounted up front and a Baader solar continuum filter with an IR blocking filter in front of the camera.
Large (39-inch x 20-inch) sheets of Baader AstroSolar safety film are available here:
http://www.baader-planetarium.com/sofifolie/sofi_start_e.htm
From what I've seen, the best Ha images taken by amateurs seem to be taken with either double stacked Lunt LS100Ha or single stacked Lunt LS152Ha scopes. I haven't seen any images taken with their new LS230Ha (9-inch !!!) scopes yet.
Many of the best images are here:
http://solarchat.natca.net/index.php/en/