For stationery and gifts i usually buy online at
www.greekgiftsetc.com or
www.greekgearexpress.com
for clothing i go to local screenprinters or embroidery places...they usually can come up with Greek letters and the prices are usually not bad, depending what you want and if its a group order...
I too have thought about opening a Canadian Greek store and have started doing some research, but i'm nowhere near financially stable enough to even attempt to start yet...