Hello, guys. I haven't found a topic on the matter so I wanted to share few thoughts about it.
This is the BIS list I came up with, looking to Ulduar 25 and 10 men hard modes.
I actually achieved the Herald title with a really similar list, missing only few items (I lost the drape to an hunter and Algalon 10 men never dropped the shoulders, so I replaced them with the mail ones from XT 10 hard mode).
Tell me what you think about it, I hope you find this helpful.

Head: http://wotlk.cavernoftime.com/item=46151 (Warrior tier 8.5, 58 emblems of conquest or token dropped by Thorim 25 men)
Neck: http://wotlk.cavernoftime.com/item=45820 (19 emblems of conquest)
Shoulders: http://wotlk.cavernoftime.com/item=46037 (Algalon 10 men)
Cloack: http://wotlk.cavernoftime.com/item=46032 (General Vezax 10 men hard mode, the only cloack in the entire game with 2 sockets)
Chest: http://wotlk.cavernoftime.com/item=46146 (Warrior tier 8.5, 58 emblems of conquest or token dropped by Hodir 25 men)
Wrists: https://wotlk.cavernoftime.com/item=45888 (Hodir 10 men hard mode)
Gloves: http://wotlk.cavernoftime.com/item=46148#sold-by (Warrior tier 8.5, Emalon the Storm Watcher 25 men or token dropped by Mimiron 25 men)
Waist: https://wotlk.cavernoftime.com/item=45161 (Ignis the Furnace Master 25 men)
Legs: http://wotlk.cavernoftime.com/item=46150 (Warrior tier 8.5, Emalon the Storm Watcher 25 men or token dropped by Freya 25 men)
Feets: https://wotlk.cavernoftime.com/item=45232 (Iron Council 25 men)
Ring 1: http://wotlk.cavernoftime.com/item=45106 (Flame Leviathan 25 men)
Ring 2: http://wotlk.cavernoftime.com/item=46048 (Algaon 10 men)
Trinket 1: http://wotlk.cavernoftime.com/item=42987 (Crafted by scribers)
Trinket 2: http://wotlk.cavernoftime.com/item=45931 (Thorim 10 men hard mode)
Weapons: http://wotlk.cavernoftime.com/item=45868 (XT 10 men hard mode)
Ranged weapon: http://wotlk.cavernoftime.com/item=45296 (Flame Leviathan 10 men hard mode)

The idea behind this set is to get enough armor penetration only to reach the cap (1400) with the Mjolnir Runestone proc.
You will need 735 armor penetration and to reach that numer you will have to use less or more arp gems, based on your professions (JC+BS is the best way, even if JC+ENG is still considered the bis combo).
Remember to use a low ilvl shield (from 200 to 226, not obtained from a dungeon or raid introduced in the game after Uduar) for your defensive cooldowns, such as Shield Block or Shield Wall, or you will fail the achievement.