Canon has not given any specific indication what their target might be for a higher-resolution full frame or medium format camera. Unless I am mistaken, the "10,000s of customers" line is not in the original.
Since 10,000 is plural, we'll use 20,000 for the short end.
For the love of...
"How many (including 1 x) 10,000s" seems perfectly acceptable, especially in Japanese.
However, the line of the original translation does not read that way. Here are the relevant couple of lines from the original:
ただ、現時点で明確な計画をお話しできる段階にはありませんが、当然研究はしています。最終的には市場からの要望を見極めて、キヤノンとしてどういったカメラを出すべきなのかを今後考えて行くことになると思います。
I don't see any mention of an actual targeted number. For "10,000s" you would expect to see the character 万 somewhere.
Google's translation:
"However, in the early to talk about specific plans at this time, but research has naturally. Ultimately assess the market demand, I will go and whether we will reach a camera such as Canon do."
The
OCN translation:
"It isn't in the stage which can speak about a clear plan in the present, but it's being studied of course. I think request from a market will be ascertained finally, and thinks what kind of camera to take out from now on and goes as Canon."
On Keith Cooper's Google+ translation line, a Mr. Ellis Vener has offered a "rough translation." It is there that the "10,000s of customers" line originates. I believe this is just his opinion of their likely business strategy, similar to how I often write what I think Canon is doing or ought to be, but usually I do not put my own words in their mouth.