A better comparison may be the RN type 45s; they cost 6.5 billion pounds for 6. The exchange rate varied over the years (between 1.5 to over 2 CAD per pound), but still probably somewhere around $1.6 billion each CAD. And that was started a decade ago. Add in inflation and another 10 years before they start and equivalent costs go up more.
http://en.wikipedia.org/wiki/Type_45_destroyer#Background
$1.3 billion per is a lot of money, but could quite easily cost a lot more then what is currently budgeted. Keep in mind the RN has the similar policy for 'regional benefits' so even though they had a better developed industry, building the modules was spread around a few yards all over the UK, then brought together for final assembly on the Clyde.
Sure, they are the cadillac of modern warships, but as they operate on roughly similar requirements as the CSC, and the RN has very similar crewing and operating philosophies as that's where we got ours from (some officer training is still provided in the UK) so it's a better benchmark then the Danish, Dutch, Spanish or Norwegian ships as their navies operate completely differently then ours (ie we aren't unionized).
My guess is the 15 ships at that budget was a WAG and unless they increase the budget, will probably realistically end up with somewhere around 10.