I know this will sound horridly ghetto but it's my 2 cents: get a couple 450 mah ego style bats, and a couple of cheap bcc and toss them inside an altoids tin. Before you laugh, hear out my reasoning. I don't have a tin to measure with but I'm confidant you could get 2 bats and 1 tank in there maybe 2 tanks or a 5ml bottle even. Obviously it won't be the greatest vape ever BUT you're only out there risking 15-20 dollars not 100-200. If I lost or damaged any setup I'd certainly be annoyed, but if I lost/ damaged a more expensive mod I'd be livid.