I know it's a bit of a drive, but the new store in Edmonton - Aquatic Exotic + had a large Duncan, with about 15 - 20 heads (about 8" or more across the top, if I recall correctly), you would have to call to make sure they still have it, as I have not been in for a couple of days. I happen to grab their card, 780-468-4661 the owners name is Candace (off the card). Their email is
Aquaticexotic@live.ca. The store is just south of Big Als so you do not have to drive through the city, coming up from Calgary.
The only reason I happen to notice is I was out buying christmas presents (2 sons, both with salt water tanks) and ended up at almost every store, looking for what I needed. (No, not telling what I got them, they read these messages, as well
).