Rogers Majestic 7R732

[Rogers flipdial]

What you could do - is contact the owner of that Deforest radio -
http://barrie.kijiji.ca/c-buy-and-sell- ... Z186277526
It should have the same speaker - and ask them for a picture of it. From the description it sounds like its an 8 inch speaker with an extension to the frame to bring it out to either 10 or 12 inch - the field coil is 2000 ohms - the output transformer would be mounted on the speaker - and is a single ended type - you can easily obtain a universal replacement for it . The cable terminates in a 7 pin plug with 5 smaller pins and 2 fat ones - standard for pretty much all Rogers sets.
If you're not in too much hurry for it - you could come to the next radio meet put on by the London Vintage radio club and make a connection there with someone to find a speaker - or go to the joint meet held in Guelph in the spring where you are very likely to find a scrap unit or fixer-upper.