http://www.bikeworldusa.com/index.ph...70d65900622b9d

Has two 21.1 stems, tall and regular. Doesn't list the extension. Maybe you can estimate it from the photos.
Also, aren't 'BMX' the same 21.1?

[edit] oop i guess the Voyageur is a road bike that should have a nice Alu stem; these appear to be maybe cheapish steel stems for middleweights w/ upright bars /