Well Amie, having been in Ontario and throughout Canada i can attest to some of the 'big fat chards' that we can get locally.
First off, if you liked the Beringer Stone Cellar, try the Beringer Founders Estate version (about $22/bottle). It is FAR more refined.
Secondly, i recommend in general most Californian chardonnays that have had 2 years of ageing and the 'sur lie' process (check out the labels). These are the ones that go through the major malolactic acid fermentation which provides that fat, creamy texture.
Third, we had a Robert Mondavi 1999 Chardonnay, Napa Valley Unfiltered the other night. Although i found the 14% alcohol a bit much, it was a characteristic fat chard for sure.
Lastly, my all time favorite, found in our own country, is the Peller Estates Andrew Peller Signature Series chardonnay. About $28 a bottle and you can get the 2002+ at this point (a little young, the 2001 is my fav), but SMOOOOOOTH SMOOOTH and creamy as carnation.
The Peller one you can find at local stores in the fine wine section or you will have to head to Niagara on the Lake for a day (get out the new jet).
The others can all be found at the liquor stores, fine wine sections although you may have to hit several stores as they do not all order the exact same wines. Call first.

Unfortunately i have not yet come across a truly fat and refined chardonnay for under $18. The new Australian Yellow Tail is pretty decent at $13/btl, but that is about as close as it comes IMO. There are many more Californian wines yet to try.

"Those who preach the myths of audio are ignorant of truth."