Hmm, I think the actual adaptors have changed over the years, and are now narrower (or is that larger?) than they used to be.
Athough, I was sold a yo-yo adaptor by Apple as a replacement for my Wallstreet power brick a while back. The yo-yo at the time was supplied with the iBooks, G3 Powerbooks and also the early TiBooks.
I guess there is a fair chance it may work, but I would be very very careful.