I personally haven't seen any servers hosting Murderball, but then again I've never really looked. Have you ever been to FPSBANANA? They have some maps under TF2 Misc/Other tagged as Murderball. Maybe you could start there and see if any ported over the functionality into a map. Otherwise try this Google search which returned some TF2 Murderball servers.
If you received an item that didn't appear in your backpack until later this is not unheard of. Usually it's a glitch or a synching error, but the item will usually be held for you and added to your backpack when it can. Restarting TF2 sometimes will help with this.
Best Answer
Some hats and misc items have multiple styles to them.
Set Style
switches between them.I'll post a list of these items shortly, as well as a screenshot or two.
These items are:
Added 2011/04/14:
Added 2011/04/20:
Added 2011/05/05:
Some of these are different models, some of these are just different paint jobs.
Here is my Team Spirit colored Pyromancer's Mask with the paint changes:
Here is my Ghastlier Gibus with model changes: