So here it is!
With this PC mod for Mass Effect 3 you'll be able to switch Tali's ingame picture with either of the ones I did: Tali with short or long hair.
You'll need to download and use Texmod
to make this work.
Just download whichever Tali you prefer:Tali'Zorah vas Rannoch with short hair
Tali'Zorah vas Rannoch with long hair
Thanks to ~yellowbeatsblue
for creating the texture! Make sure to check out her Tumblr: [link]