There's a rare US-developed breed called the Treeing Walker Coonhound. Looks a bit like a Beagle with longer legs.
Once they were just called 'Walkers' or 'Treeing Walkers'. Here's a link:
http://www.treehound.com/treehound/html/walker.html

Mightn't be the breed you're looking for, but It's the only breed I could find that had the word 'Walker' in its name.
Marie