Well after looking around online I found a site selling tiny pumps at reasonable prices. TCS Micro Pumps only £36.00 !!! Sure the flow rate of 250ml/min is quite high but if you put a few resistors inline to drop the voltage to the pump all you would need is a button to trigger the pump for a sec every now an then. Im sure it wouldnt be too hard to mod one into a box mod or something, its 27mm x 14mm x 20.5mm. I just need to scrape up 50-60usd and get one.