I am happy to report that I have installed the paparazzi autopilot in one of my airframes and have done some ground testing. So far the results are positive. The telemetry works well (at short range at least), and the aircraft reports proper position and attitude. When the aircraft is held at an angle, the control surfaces move to compensate, and the behavior of the control surfaces looks correct.
In the picture below, all of the autopilot system except for the radio modem can be seen.
In this view of the fuselage interior, the radio modem is visble.
This is a detail shot of the installation of the horizontal infrared sensor.
This is a detail shot of the installed vertical IR sensor.
And finally, a shot of the interior of an RC reciever that has been hacked to output the PPM signal on the channel 8 PWM pin. The cut trace to channel 8 is hidden by the capacitor.
I have a bit more ground testing and configuration to complete, and this plane will be ready to fly.