It appears that RadioShack hasn’t only pulled it’s physical stores from Canada, but also won’t ship parts purchased at their website to Canada (owing to an interestingly tortuous licensing tiff).
Legal trivia aside, this is a total pain for Canadian readers of SNIP, BURN, SOLDER, SHRED, as several projects (specifically the Ticklebox and Spring Reverb effect) rely on an outmoded audio transformer that’s pretty idiosyncratic to the Shack.
Canadian maker Andrew Gray brought all this to my attention, and was kind enough to be a components guinea pig on behalf of his soldering-iron wielding fellow citizens. We’ve established that the RadioShack 1000:8 ohm audio output transformer can be replaced with the Xicon 42TM013-RC sold by Mouser.com as Mouser part #42TM013-RC. This transformer doesn’t have the handy color-coding that the RadioShack one does–and also will likely come with six leads (three on each coil), instead of five (three on one side and two on the other)–so you’ll wanna take a look at the datasheet or poke around with a multi-meter before you start soldering.
The SPDT relay I use for the Ticklebox is a little easier to source, several workable versions available through several vendors; Andrew has confirmed that the Omron G5LA-14-DC12 (Mouser part #653-G5LA-14-DC12) works great–and is about half the price of the RadioShack component I used (the audio transformer is about the same price as the RadioShack equivalent). Score one for the Maple Leaves!
Thanks for your help and patience, Andrew! Everyone else, back to soldering!