It took some fab work, but I was able to adopt some go-cart calipers to the stock rear rotor to act as a parking brake. I used the stock e-brake handle.
This is the general style of caliper I started with.
http://www.mfgsupply.com/m/c/218070A.html?id=FL2LPsEu I build a spacer to distance the pads to clear the rotor and designed a bracket out of alum plate to mount to the extra bolt pattern on the uprights (uprights have bolt holes on both sides). Remember that the calper must float a bit to deal with clearance on the rotor. I used the stock Ebrake handle but needed a simple e-brake cable better adapted to the brake assembly for the caliper. Just a ball on the end of the cable style to thread through the brake lever is enough to pull the lever and hold the car.
Seems it would work great for a few weeks then need an adjustment, the lever throw was limited and would require exact clearences/adjustments to prevent binding but at the same time hold when activated. For passing inspection it could cost less the $100 to fab. I did both axles which I think contributed to the challange. If you could get away with just one, it would be much simpler to build and use as a temporary solution.
I finally pulled them off last summer after I decided the extra weight was not adding much value. I would not suggest it for a long term solution, but perhaps for a cheap "get through inspection" answer it might be worth the effort.
Since they are in a box, I can pull them out and send over any photo's of interest. Easier to provide a direct email address so I do not have to reduce the image size and post. Like I said, kind of works but not optimal.
V8 Capri, I get to Mel once every 4 month. Have a mate out in Frankston who I see everytime I get out there.
I will look you up on my next cycle down under. Can hand carry some parts if needed.