It's still a struggle to find the 64GB Nexus 6, but they do appear on occasion if you don't mind waiting. The 32GB is in stock pretty consistently, but the blue 64GB has just broken cover on Google Play and Motorola. A mere $699 plus tax and it's yours.

2015-02-13 17_16_34-Nexus 6 (64GB, Midnight Blue) - Devices on Google Play

The base price is the same at both stores, and you'll have to pay tax, but Motorola ships to most US locations free. Google charges $10 for basic 3-5 day shipping, $14 for 2-day, and $19 for 1-day. The upshot to ordering from Google is it tends to (in my experience) be better at dealing with warranty issues.

No telling how long these devices will be in stock, so get on it. This is also US-only, of course.