Unitrade 90bd catalogs at $28,000 CAD and could be the most expensive 20th Century Canadian stamp(s). Released July 1, 1903 so just made the turn of the century. It is two Imperf Booklet panes together in tete beche format. There are 2 for sale on
ebay for $22,795.00 each. Just do a search for Canada with the sort of highest price first.
There is also a 77b booklet pane in this format that catalogs for only $25,000 released June 1900. There are Admiral Booklet panes with the Pyramid Guide tab that catalog in the $4000++ range
If you take into account the No Hinge percentages, the 50c Edward in Very Fine condition catalogs at $5250. The 20c Numeral Issue Imperf pair catalogs $7000. The Admiral Imperf pairs are in the $3000-$4000 range with the Imperf Gutter blocks at $10,000 each.
There are a couple of Admiral Lathework singles that are pricey, the highest being Unitrade 108 3c Brown with Special Lathework at $10,000. There a a fair number of lathework blocks over $5000.
Many of the Imperf pairs of the stamps starting at the Scroll Issue are high priced, the Bluenose cataloged at $12,000 in Unitrade.
The Port Hood Provisionals, Scott 88B and 88C - $20,000 but they were released in 1899