Wilfie,
I would start by trying to find a local fish club or aquariam society.* I will envy you if you find one.* I am a member of 2 clubs, but the closest one I belong to is 5 hours away!* Here's a link to get you started:
http://www.fishlinkcentral.com/links...merica/Canada/
Also try by searching using Aquarium Club or Aquarium societies as the keywords on google or whatever search engine you use.* There are other sites out there that may have more clubs listed.
Once you have checked out the local clubs, I would join them, and get to know the other members.* So far, everyone I've met in my clubs are great folks and they are more than willing to share stuff they have or sell stuff to you at a much better price than buying from a store.* I will keep my eyes open for you, and give you leads to any I see for sale.* There is also a specialty site which folks post mainly about all the shelldwellers, not just the multies.* Their classified section might be a good place to look also:
http://www.shelldwellers.com* * *
P.S. If you were willing to take a road trip, the above site folks just rave about the quality of the fish, and the availability of shelldwellers at this site:
http://www.wetthumbaquatics.com/