Brewer,
I think that the surface mine/solvent plants have the lowest production costs these days. Syncrude and Albian Sands have such plants. Unfortunately, these are joint ventures, so not good pure plays. I gather that SAGD (steam-assisted gravity drainage) plants are cheaper to build, but cost more to operate, requiring natural gas to make steam. However, most of the bitumen in the oil sands is too deep to dig, so injection processes are the future.
The cost of building a plant is probably more important. A mine/solvent plant seems to realistically cost about $40,000 CND/barrel of average daily production (~$34,000 US/bbl). I estimate that this gives about an 8-year payback (heavy crude is discounted). If a reasonably sized mine/solvent plant (say, 100,000 bbl/day) could be built for half that, the payback would be really exciting. I think a smart company could build a good plant for less than $40,000/bbl.
CNRL is building a mine/solvent plant and Imperial Oil (=Exxon/Mobil) is going to. Imperial is a partner in Syncrude and should be able to take advantage of a lot of experience in their design. I am watching Imperial and their cost estimate.
I think it is better to look at how well the parent oil company does. Do they replace every barrel produced with a new barrel? What is their return on investment? etc. These oil sands operations are typically only a small part of the assets of large companies.
Gypsy