I saw at the store there's a new cooking oil composed of 80% canola oil and 20% olive oil. They offer it for frying and seasoning. What would be the smoke point for such an oil?
It would be the smoking point of the lower of the two oils.
There is a persistent myth among cooks that mixing two fats somehow makes for a better smoke point (usually oil+butter). But the molecules which will burn at 150°C will always burn at 150°C, no matter what other molecules they are mixed with. So, if you mix two oils, and oil X has the lower smoke point wlog, it will smoke at the smoke point of oil X. It will smoke less than pure oil X, but only because you have diluted it and you have less low-temperature-burning molecules in the pan.
This doesn't mean that the smoke point of your mixed oil is too low for frying. The smoke point of cold extracted oils is always low. But it is possible to refine olive oil, even though nobody sells it pure (the advantages of olive oil are removed by refining). If both oils in your hybrid oil are refined, it will have a high smoke point, suitable for frying. But marketing doesn't always care about such details, so, if they don't say anything more specific on the label, you can't know what kind of olive oil (or canola, for that matter) they used. From a cynical point of view, this is a perfect way to get low-quality olive oil, refine it, and sell it for frying hoping that the customer will choose the frying oil advertising "olive oil" among its ingredients, but there is no proof that this is what the producer is doing.