Looking through online ammo vendors...
 

I'm looking for the Hornady Superformance in 6.5x55, but alas I cannot find them. Is there a vendor you guys use that has it? Which vendor do you think has the best selection of ammo?

There's no Hornady listings for that caliber, but try this site. It's an internet search engine dedicated to ammunition.

Home page:
http://www.ammoengine.com/

6.5x55 search results:
http://www.ammoengine.com/find/ammo/...sort=1&group=2

Natchezss.com, Grafs.com, Midwayusa.com, Powdervalleyinc.com, Ammunitiontogo.com, Cabela's.com, Bassproshop.com, and I'm sure there are a bunch more, but those are the ones I often check.

I called Hornady. They haven't loaded that one yet for retail. No wonder I can't find it!