To start, the shoulders. I listed the ones that are usable by any class, the Spaulders of Manifold Eyes from Heroic Beth'tilac. They are the same as the Heroic Paladin tier gear. So you're looking at H Beth for these shoulders! Or you have a second chance, if you are a paladin, getting your tier piece off H Majordomo.
Chest, legs and gloves - Hyperion. Farm MC. A LOT!!! It does drop in other level 60 raids but the best drop rate I've found for Hyperion is Molten Core. Make sure you have lots of space in your bags, other good transmog stuff drops as well, not just plate. You can earn a pretty penny AH'ing the extra greens. Plus, Garr in Molten Core drops Drillborer Disk, the shield I have listed with this set.
Now the legs, they are part of the Hyperion transmog, however there are two other look alikes, both listed on Wowhead. The easiest to get is probably the Lavacrest since they drop fairly regularly off Bael'Gar in Blackrock Depths. The Khorium Pants are a sure thing IF you can find a blacksmith who has the pattern. Good luck farming the pattern, it's a rare drop.
Oh yes, the belt. I did not use the Hyperion Girdle because it doesn't do much for me. I used the Bloodfist Girdle instead. The color matched and the smooth gold background helped draw the shoulders and shield into the set. Plus I just like it.
If you are a blacksmith who played in Vanilla and did all the quests and farmed lots of patterns and are a Master Swordsmith to boot, you can make the legs, boots, and the sword. There is also a different set of gloves that I prefer over the Hyperion ones. The Fiery Plate Gauntlets are the same colors and basic style only a bit more streamlined and lot less clunky. The pattern however is from a quest that no longer in game.
|Shoulders||Spaulders of Manifold Eyes||Heroic Beth'tilac|
|Chest||Hyperion Armor||Random Vanilla Green|
|Belt||Bloodfist Girdle||Random BC Green|
|Legs||Hyperion Legplates||Random Vanilla Green|
|Boots||Hyperion Greaves||random Vanilla Green|
|Hands||Hyperion Gauntlets||Random Vanilla Green|
|Main Hand||Blazeguard||BoP Crafted|
|Shield||Drillborer Disk||Molten Core - Garr|
So there you go, Charlotte. That's my fiery red set! Enjoy putting it together. I also do requests if you have a specific item or theme you want for your character. I'd be happy to help you put together a couple different sets to pick from. And yes, I do more than just plate. /wink