This bug fix is very hard to find since it requires knowledge of graphics programming to figure out what has changed in the wow rendering system that breaks our web rendering system. Needless to say we don't have very many graphics programmers on the web side of things so bugs like this can take a while to find ourselves, or take a while to coordinate with the game teams.
As it turns out however we had a bug where some of our pet renders were blank (I do realize that some pet and mount renders are STILL blank and have bugs... we know). It turns out the fix that I stumbled upon to fix the majority of blank pets in 5.3 also fixes this hair issue. I'm sorry it took so long to find this.
QA is currently testing my fix on profile renders now and if it all looks good I'm hoping to get it our early next week.
Thank you so much for giving us an update on this!
We are looking forward to having hair (beards, helms, etc.) again!
The QA testing is looking really good. This also fixes a couple of the hidden-shoulder bugs that have been reported.
I'm unfortunately gone for most of the day today, but just got word that the update to the rendering blades just went out. You should start seeing hair upon logouts. I'll be checking in later tonight, but let me know if you get an updated render and it still looks wrong and we'll look into it.