Kr4m123, you can't get an OFFICIAL MineCon cape that EVERYONE can see, but you could use a mod called Mccapes to make your own cape or select capes from their website. However, this way, only people with the mod can see your cape, compared to the entire community seeing your MineCon cape.
The whining is strong in this thread already. Life isn't always fair and you can't always get what you want. Capes are a exclusive bonus for those who attend minecon and likely always will be. Trust me they don't get you any special treatment.
I think he meant that they should have made a new design, because it's not exactly a new cape.
For the first MineCon, there was a poll. They asked the minecraft community which cape they liked best. The MineCon cape for 2012 is just recycled from the choices; it was the second most popular. Perhaps for next year's MineCon, they'll just choose the third most popular cape and so on and so forth.