Notes

No vendors gear higher than white quality, no auction house, no trading, no mailbox, no dungeons, obviously no heirlooms no quest items/gear, Basically the ONLY gear you are allowed to wear are items that you either loot from world mobs or that you craft yourself via professions.
Now, this is the cool part/twist. I personally think deleting your character is too much of a consequence for dying, so what I have been thinking is that. Yeah you can die, but if you do you have to choose one ability to prohibit yourself from using. For example, say I'm a hunter and I die, I have to choose an ability to get rid of say track beasts. A non useful ability but then if you die again you just keep losing abilities to use for when you get to the end game wrecking ball challenge.

MORE RULES -

No enchantments on your gear (DK Rune Empowerment is an exception as it is a class skill).
Tabards (white quality only) are allowed as long as they do not provide a boost / gain / skill that your character wouldn't normally have. These tabards are NOT allowed:

Argent Crusader's Tabard - allows you to teleport to Argent Tournament.
Baradin's Wardens Tabard - allows you to teleport to Baradin's Hold Alliance Camp.
Hellscream's Reach Tabard - allows you to teleport to Baradin's Hold Horde Camp.
Any Green, Blue or Purple quality tabards.
Cannot join a party, raid or group with the intent of getting help to further yourself in the challenge.
Since guilds are ALL level 1 now, guilds are allowed.

Account-wide Abilities: Not Allowed. The basic idea here is that you should be using what would only be available to your character if that was the only character on your account. This includes:

Heirloom Mount
Flying in Warlords of Draenor
Mounts w/ Extra Abilities (ie. Water Striders, Mounts w/ Repairs/Vendors) unless you actually earn them on your challenger.

General rule of thumb: Play your character like it's the only one you have on your account. Don't use your account-related bosts like the Water Strider mounts or anything else you wouldn't already have on a single character for the account. Receiving anything from another character is against the spirit of the challenge: no gold, gear, bags, etc. Play with what you have been given for your lone character.