Blizzard has released a glimpse of each of the official Argent Tournament Mounts for the Alliance and Horde factions.  These screenshots allow you to see how they look like in advance. Some will have further changes though. These are the ones you can purchase with 5 Champion Seals and 500 gold (or less).  The images also show you the graphics for the Faction Flags. Pretty items to show off.

Blizzard Quote:
In an upcoming content patch, faction mounts offered by vendors on the Argent Tournament grounds will be updated, and the mounts being offered will match the colors of the faction you choose to represent. What better way to champion the triumph of your legion than draping yourself in the colors and symbols of your allies?

Mounts already purchased at the Argent Tournament will be replaced with the updated mounts when this patch goes live. For those looking to get their hands on even more sweet rides, ten mounts using the original tournament look will be available for purchase from Argent Tournament vendors for 5 Champion’s Seals and 500 gold (faction discounts apply). To purchase these original mounts at the Argent Tournament, players must be either members of, or exalted with, the corresponding faction.

For those interested in hitting the tournament grounds when the patch goes live to check out the different mounts, all faction valiants will be riding the original mounts, while the updated mounts can be seen in the stables or ridden by faction champions.