You might want to consider the Mark IV underdash a/c unit by Vintage Air. Externally it's an exact metal replica of the unit built in the '60's and '70's with modern interals for reliability.
http://www.vintageair.com/08/catalog08/08%20VA%20cat%20pg%2023%20f.pdfHere's a response from another site posted by a Vintage Air rep.
"The Mark IV is a great new product just released from Vintage Air and is selling great....it also works as good as it looks. The Mark IV evaporator list for $299.00 and is a cool only system so normally you will retain your OEM heater. The evaporator is just one component of an A/C system, you will also need an compressor, bracket, condenser, hose kit, drier and safety switch which normally runs in the $880.00 - $900.00 range but could be a little less or more expensive, depending on what parts needed to fit your ride. The evaproator itself is 15.5"W x 5.75"H x 13.5"D.
All of the guys in VA Sales/Tech Depts are gear heads and lurk around the HAMB daily (don't tell Jack). Most of us have attended/participated in every Lone Star Roundup and think it's the best show in the country. We think the HAMB Alliance is a great idea but being a manufacture with a large dealer network, we do not want to be in pricing competition with them and sell @ retail only. I know several HAMBers who are VA dealers so I would recommend seeking them out and keep it in the HAMB family.
If anyone has a question about the Mark IV or any of the VA systems, don't hesitate to contact myself or any of the guys in the Sales Dept....we are here to help out any way we can!!"
Thanks again,
Mark Hungerford
Vintage Air Tech. Dept.
1.800.862.6658 ext.111