Yeah, 100% foil for the tuck box on a project like this would drive the cost into the stratosphere - but metallic inks, while a little less impressive, are a good deal more affordable and worth considering, perhaps with some foil line work.
Current plans: two Editions of the deck will be printed... Unlimited edition (USPCC) with borders, standard box. Crushed BEE, metallic inks. Limited edition (WJP) - borderless, 5-6 colors of foil on tucks, possible embossing, internal box printing, new card stock (never saw such soft paper offered by Asian printers).
Main reason to print one edition with WJP - 5-6 colors of foil for the box (very expensive even in China) and small print run of 500 decks.
I am going to share a Kickstarter preview link here in 2-3 days. Planning a campaign on Sunday morning NZ time, Saturday US time.