First off, I think you want to stick with "litho" units. I don't think most of the screen print units have a vacuum bed.
Next, I would suggest that you consider purchasing a unit used, via eBay, Craigslist, or via a website (that I can't find the link to) which is like a classifieds service for the printing industry. Units can often be had for just a couple hundred dollars. Keep in mind that a bulb for some of the units may run in excess of $150.
The 26-1ks (current model), and the older version, 26-1k, are both popular. There is a 40-1k, which is similar, but has a larger vacuum bed. I use a NL22-8C, which is slightly smaller and simpler, and there are also N750 and N1000 units, which are both fully-enclosed units.
Lastly, keep in mind that Nuarc was just one manufacturer of "plate burners", you may be able to find something similar from another manufaturer, perhaps one that was more widely distributed in Canada.
Good luck in your search.