instead of moving the firewall/cowl back, could you add the inches you need in the top of the roof above the doors and leave the doors full length? the roof pieces you cut out to shorten it may work for this idea.
Moved the thread because the early pictures were corrupt. I could have added the metal in the roof, but it isn't square up there and it would be a little more difficult to add metal then to take it off the doors. Check out the newest thread, im effectively ending this one. Thanks, Zach.