Hang out on
www.turbosport.co.uk
This seems to be the forum that most of the Cossie Powered Escort boys use.
Also keep an eye on out
www.oldskoolford.co.uk too as there are some guys on there.
They crop on e-bay pretty regular too.
As Paul says... with any old Ford start with the best shell you can get.
They were never designed to stand the torque that a cossie motor can generate so when you look at a car check to see if any additional prep has been done on the shell.
Seam welding, gussetting, cage etc