i had a manual one for a while, but it seemed like there would be too much work get latches that would work. i'd say $300 if in bad condition and $500 if its in real good condition.

 

You could convert it pretty easy to power. I have one of the bronze glass roofs without the frame and the rear parts where the arms fit into are just the regular stock pieces that have the tabs cut off and a plastic trim piece wrapped around them. A hole drilled in the center bottom holds them to the roof using a screw.