W Axel, most mods are designed to run on 14500, 17500 and 18500 Li Ion rechargeable
batteries. They are a bear to find locally, but are easily recharged numerous times with the proper charger. If you go that route get protected cells and I recommend AW
batteries, you can do a search in Google, but it's easiest to find him a candlepowerforums.com or buy them from lighthound.com. The are more, but the heavy use flashlight guys swear by them.
I know crashtestjeep had a Chuck built for the VK cartomizers, I'm not sure if they got all the bugs worked out of it yet or not, but they are working on making it perfect, so there are reay mades trying to adapt to them.
There are also adapters made, you can use VK carto's on a 510 and visa versa.
Then there are homebuilts. laser pointers converted, flashlights converted etc.
Then "box mods" that basicly you take a plastic box and fill it with as many AA rechargable batteries as you can to get the voltage and amperage you want.
Look in the modders forum, you will be good and confused after an hour or so!