I've used hand holds and other mounts through the tie down ring at the top of the strut. You need to ensure that whatever you're mounting out there won't interfere aerodynamically with the operation of the aircraft at all angles of attack and at all configurations. Generally there's a speed limit to consider, as well.
Sometimes it's easier to use a side looking camera from an open doorway looking slightly aft. You can still get very good shots this way, with more camera control.
An older STC is available for certain single Cessna's for a wing mount camera:
Supplemental Type Certificate
STC Number: SA4-662
This certificate issued to:
McBride Clifton G
STC Holder's Address:
620 Rollingwood Drive
Vallejo CA 94590
United States
Description of the Type Design Change: Camera pod.
Issued, 01/01/1961
Responsible Office:
ANM-100L Los Angeles Aircraft Certification Office Tel: (562) 627-5200
TC Number -- Make -- Model:
3A12 -- Cessna Aircraft Company, The -- 172
3A13 -- Cessna Aircraft Company, The -- 182
5A6 -- Cessna Aircraft Company, The -- 180
A-799 -- Cessna Aircraft Company, The -- 170
You can also visit information about the above STC at:
HOME
Pictures are available there, as well as a means to contact the STC holder.
This particular STC is different than what you're presently looking for, but it's a starting point, and you may find some direct connections to help build or approve what you're after.
The FLIR (Forward Looking InfraRed) system mounts sold here may also provide you with some alternate options, including the ability to pan in other directions, with some adaption:
Paravion Technology, Inc. - FLIR Airborne Infrared Camera / Sensor Mounts
Depending on what it is that you're using for a camera, you may be able to film through the prop arc, from inside; obviously not a first choice for a high quality shot, but again, it really depends what you're trying to capture.
For your own purposes, one of your biggest enemy will be vibration.
Visit this site for information and safety related material on cameras, mounting, and aerial photography:
Aerial Cinematography: Safety
This mount may fit your bill exactly, depending on what it is that you're using for filming. Pan down to see the wing mount camera system:
Aerial Filming techniques - aerial camera mounts ; Last Refuge ltd.-page 9 of 9
Aerial camera wing mount system for Cessna from Last Refuge