You can learn a lot about Novatacs by reading my other posts in this forum.
Prices vary greatly depending on the seller.
No, Novatacs and HDS are not semicustom,
They just cost more because they are sold by people that live in USA, where cost of living is more expensive.
They are also marketed to the Military, which has an unlimited budget (taxpayer dollars), to pay exorbitant prices.
I sometimes help friends overseas by shipping lights to them. PM me if you would like my help spending your money. 
I do not charge any fees, I only do it to share the Love, (or obsession)…
There are also remailing services, that will take delivery at a USA address and then forward the mail to you, for a fee. (I have no affiliations to remailing services, just sharing options)
fwiw, HDS lights are almost as large and heavy as some 18650 lights:
the light on the left is 18650, the others all use 16340
Were it not for the fascination I have with programmable and ramping UIs, lights with Cult Reputations, and rotary dials, I would just buy a Zebralight or an Emissar D4