Just to bring this one ot the top..
Been looking into this, still not 100% sure.
The CBS kit linked above is about £680 once you buy the condenser, I did a quick search on vintage air stuff at summit racing and reckon you can put together one of their systems (less the hoses) for less.
very roughly:
Evaporator $410
Nice switch panel $160
Drier/trinary valve $60
Condensor $140
= $770, or about £520.
The only thing this CBS kit includes is some hose ends, which might/might not be of any use.
Granted you have to get it shipped, but theres several people bringing stuff in from the states now.
I'm just figuring out the install in the car and if I need a fan for the condenser or not..
Obviously if VA do a kit for your car then you can get one of those, I think they are about $1200 and include a compressor and some vehicle specific bits and bobs.