The 603/903 were never made available in North America (probably because of the 3g capabilities, as Mr. Dulin pointed out). The non-3g (and non-touchscreen) 602/902 are sold over here. Apparently, the upcoming 612/912 models are just like the 603/903 models but with the 3g hardware removed. So, they should be available in North America when they are released sometime soon.
I would stay away from the old 3XX models. The latest models (6XX, 9XX and 360plus) have a newer software base that is incompatible with the older models. The older models will likely receive fewer and fewer software updates.
I bought my 902 from Dulin's Books in the US and had it shipped here to Vancouver without problem. It was shipped by USPS (to avoid the obscene UPS/Purolator brokerage fees) and arrived here in a few days. I wouldn't be nervous about ordering from any of the US distributors (except that the Canadian dollar may drop significantly by the time the 612/912 come out

).
Edit: I should add that "touchscreen" on the Pocketbook E-Ink models means a Wacom digitizer. So you have to use a special pen with it; fingers won't work. If you want a finger-friendly touchscreen on E-Ink, you'll need to go with a different brand (like Sony).