It looks like the best way to get a discounted price on the new Canon EOS 5Ds, Canon EOS 5Ds R, or Canon EF 11-24mm f/4L USM is to pre-order from Canada:
Camera Canada, an authorized Canon Canada dealer, has the Canon EOS 5Ds for $4099.00 (Canadian $), the Canon EOS 5Ds R for $4299.00 (Canadian $), and the Canon EF 11-24mm f/4L USM for $3499.00 (Canadian $).
After adding shipping (about $40) and converting to USD at current exchange rates, the final price is $3353 USD (vs $3699 from B&H) on the 5DS, $3515 USD (vs $3899 from B&H) on the 5DS R, and $2866 USD (vs $2999 from B&H) on the 11-24mm. That’s significant savings for newly announced items!
Readers report that they’ve never experienced tax, duty, or other border-crossing fees when purchasing from Camera Canada, so the price paid to the store should be the final price. The store will also optionally bill you in USD (at the prevailing exchange rate at the time the item ships), but it’s important you select the “Contact Me” option as a payment method during checkout and mention this. As another benefit, you won’t be billed until the item is ready to ship. Pre-orders will be filled in the order received.
Historically, Canon cameras and lenses from Canada have come with Canon USA and Canada warranty cards that indicate that the item is warrantied in both Canada and the USA, and readers have never reported trouble with obtaining warranty service from Canon USA.