I've wanted to do this for some time, and finally pulled it off. My first attempt ran off a pair of AA's, but 3v didn't really do it for me. I needed more power, so I decided to try building one around a 9v power source. I'm going to make one that is Lithium Ion powered so I can recharge the batteries, but I want to see how long this 9v can hold out.
Basic setup is a 3"x2"x1" Radio Shack project box, momentary switch, on/off switch, 9v plug, 9v battery, atomizer port from an old Boge Revolution V2, and a Boge LR cartomizer. In all, it cost about $10 to make, and hits like a frieght train. I had cartomizers that didn't work right anymore (would get saturated with juice) - this brought them back to life. Not quite sure how long the battery will last, but I've got a 10 pack from Lowes so hopefully that will give me a bit of a reprieve before I incorporate some protected lithium ion cells.
Most likely I'm also going to order the M7x0.5 tap & die set so I can make my own atomizer ports as well... Don't get me wrong, I love my Boge RV2, but the quirks of a bottom feeder (flooding, etc...) were driving me nuts. For 1/5th the price I don't think I did too bad...
1x 270-1801 3"x2"x1" Project box: $2.99
1x 275-1547 Mini SPST 0.5-Amp Momentary Switch $.92
1x 275-409 3-Amp SPDT Sub-Mini Slide Switch $1.84
1x 270-324 Heavy-Duty 9V Snap Connector $.53