I just rigged up my X-Fire with a 80x80m Sunon fan I ripped from a computer psu. It is designed to run off of 12volt dc which Is what I am gonna run it at.
Since I play woods all the time and am not a speedball guy I didn't care about size mainly how loud it is and good air flow.
I have the fan stuck in front of my mouth sucking air out of the mask. I then have some quick disconnects wired to the ends of the wires of the fan. To whose I hook up about a three foot long wire that goes to my "black box" which is on my belt. My black box is a 7"x5"x3" black project box available from radio shack. I have two switches on the outside and two outputs. One is for the fan and the other is for any 12volt accesory if I need one.
I am powering this off of 8 D cell battery wired in series to produce 12 volts DC. I don't have any exact numbers about the run time yet but my fan is rated at 1.2 watts at 12vdc, so it should last a long time. I'll probably have to change the batteries once a year since I don't go paintballing much.
I way over-enginered this project and went over my budget but it will be very easy to upgrade in the future if I so need to.
Also it will take all of 15 minutes or less to wire up an extra switch for 6 or 12 volts for my fasn or accesory.