I am not sure why people keep recommending the MVP to you since you have stated external batteries as a requirement.
I got a VTR a couple of weeks ago and would happily recommend it, I think you can pick it up in the states for about $80, the build quality is good, it easily fits in a pocket with its recessed tank. The only downside is that it is heavy, but I actually like that so it's more a preference thing.
I'll second that. I really like my VTR and it uses 18650s - both the flat-top and button-top versions. I got mine at my local B&M for $95 CAD