i was thinking about a sliding ragtop and came across this site before on an internet search. it seems to have a lot of options and should be easy to find one to fit the way you want. another idea would be to look for a brand new wrecked jeep liberty with the sliding ragtop. it might not be a cheap option since only the newest ones have them, but i bet they are designed well seeing as how they decided to use it on a 2008 jeep.

http://www.streetbeatcustoms.com/ragtopsunroofs.html

i think im leaning toward either a removeable lexan panel or if i can settle for a smaller opening maybe put in a roof section from some car with a normal sunroof. i think some of the older Saabs have a manual sunroof which eliminates all wiring...