Aight , so with this exploit you can get the benefit from 4 Major glyph for one arena match, then you will need to do it again for every other arena match you queue, it takes 5 seconds to do so its not really a problem.
Step 1 :
Make sure you have glyph of Inner fire as one of your 3 Major glyph when you queue an arena. Glyph of Inner Fire - Item - World of Warcraft
Step 2 :
Now enter the arena game and buff yourself with Inner Fire.
Step 3 :
Change your glyph of Inner Fire for any other Major glyph you want to use before the gates open.
Step 4:
You now removed your glyph of Inner Fire and equipped an other one but you still have the improved effect of Inner fire even tho you don't have the glyph anymore. ( free 4% dmg reduction from armor ).
Conclusion :
Queue an arena with glyph of Innerfire --> join the arena game , Buff inner fire --> Change the glyph before the gates open --> Profit
The only downside is that you need 2x Dust of Disappearance every game which is about 20g ( depending which vendor you buy it from and your reputation with them ), I don't think its alot specially at high rating.
Note that this exploit might work with other class and other glyph following the same method.
Screenshots:
1st : My armor without the glyph of inner fire
Imageshack - wowscrnshot032611115911.jpg
2nd : My armor WITH the glyph of inner fire
ImageShack® - Online Photo and Video Hosting
3rd : My armor after Swapping the glyph of Innerfire for glyph of fade ( same as if I had glyph of innerfire )
ImageShack® - Online Photo and Video Hosting
Enjoy , its a minor help but still something that can be nice at high ratings ^_^