Check out Fire Mountain Gems. They have a jewelry makers catalog. I don't know if they have the exact crosses you're looking for, but it's worth a shot. The website is either www.firemountain.com or not sure. Haven't been there in awhile.
Those are called headpins. You can get inexpensive (not high quality) ones at Michaels or other craft store. If you want to make higher quality jewelry, I recommend one of these online sites to get your findings: www.artbeads.com www.fusionbeads.com ...
what kind of pendants are you looking for and what are your goal price and your buying quantity? if you want to buy them in bulk from china, you can contact me for that.