Take a look at US Ebay, search for chargecooler or water to air intercooler..
It is a possibility to mount it in the rear aswell, as long as it is big enough and you get enough airflow, I am in the middle of my DIY SC-conversion at the moment, and I have bougth a rad that is 17x50cm and I am mounting it in the rear of the car, also changed to Turbo inlets to get more airflow. Hitec and Courtenay used to mount the rad. in the rear, and the peolpe who run their old conversion doesn`t seem to have any problem with the heat.