So after a good search, my mate (who's premises I'm using atm) and I decided to go halves on a second hand one of these:

http://www.abac-support.co.uk/individua ... 41_270.htm
At around £1600 RRP, we could afford a brand new one, but this has seen little use.
It's a huge beast with a 270 litre tank, and a 10 HP motor, which gives me more air than I'll ever need. I won't bore you with too many technical details, but it uses a two-stage pump (one large piston, one smaller one) which compresses the air in stages. This is more efficient and introduces less heat. It also has intercoolers between the stages and an aftercooler, so the air going into the tank is nowhere near as hot as with most compressors.
It also has such a large capacity that it hardly ever runs, which is all good. Duty cycle is as low as 10% for the one or two panel jobs I'm doing.
We got it wired in and I've also fitted a modest pipe system, which ensures the air is a cool as it possibly can be so all the humidity condenses out, and it allows this condensate to run downhill and be drained away. A water trap/filter/pressure regulator is the final stage in giving me nice clean dry air, ideal for painting. We may end up moving premises soon so I haven't gone for a full distribution set up yet, but this system seems more than adequate for a single user, and has cured my water problem.
The connectors are parts of the Sealey Fast Fit Air Supply System, but I've substituted the Nylon pipes for copper, for increased cooling effect.


I've copied this post over from another less technical forum, so forgive some of the lingo
