help: Toronto->Vancouver->Las Vegas

Hi,

I wonder if anyone has any suggestions for air fare
for a trip from Toronto to Vancouver then to Las Vegas,
whereby I would rent a car to visit the Grand Canyon.

My goal is really to visit Vancouver & Grand Canyon.
Vegas is optional, but I believe the air fare would be
cheaper in Vegas, so I might drop by if it's within
my budget. Ideally, I would like to fly back from
Vegas to Toronto.

I figure I would like 3 days in Vancouver, and 3 days
around the Grand Canyon.

Checking the online discount Canadain airlines (WestJet, CanJet, etc)
it seems that they all have some good rates, but never from
a originating from a US city (Vegas). Anyone have any ideas?

Thanks,

Jim