I can get organic bison burger for $2CDN/patty. Each patty is around 165g, it seems fairly lean, but about how much of that could I expect to be protein?

Not sure, but it does depend on how it's prepared as well. I've had bison burgers before. They taste very good, I actually had a hard time telling the difference between regular beef and those.

I've had my share of bison burgers plus bison steaks ... not to mention antelope, deer, moose, ostrich, etc. I can't tell you all of the figures but bison meat has a higher percentage of protein then beef and less cholestorol. After some quick searches on the internet and from just skimming, it says about 30% more protein and 25% less cholestorol. Here is a website that compares bison, beef, pork and chicken and I think will answer most of your questions.

http://www.tonysmarket.com/foodhealth/bison_info.cfm

Great site, thanks! That covered what I needed to know.