I worked out the winners (from Random.org site) soon after the competitions closed, but had to clear out my mailbox before I could notify the winners (and haven't had much time to do that, and other things here, lately).

So, to not drag this out any longer, the winners of each are:

Competition 1 - Paul Agnew (TF2 Rotorwash Rumble (Arcee Vs Tailwhip))
Competition 2 - llamatron (TF2 High-Speed Spy Battle (Twins Vs Sideways))
Competition 3 - meangreen (TF2 Bombing Run Battle (Bumblebee Vs Grindor))
Competition 4 - mknell (TF3 HA Whirl (not released in AUS) & HA Backfire)
Bonus prize - 1Azreal1 (Entertainment pack)

Each has been notified, and I'll be sending off the items as soon as I can.