The Mastermind Toys outlet in Waterloo, Ontario, has three of the new summer sets in stock! The sets in question are Skull Warrior, Skull Slicer, and Skull Basher - exactly the sets needed to build one of the combiner models. Mastermind is selling them for $17.99 (CAD) each, which is a bit of a markup, but I purchased Skull Warrior nevertheless - it's still the cheapest and timeliest option for me. If anyone lives in or near southern/eastern Ontario, check your local Mastermind Toys!