My tag team combinations:

Kitana + Mileena

Sindel + Kitana

Sub-Zero + Scorpion

Sonya + Jax

Lui Kang + Raiden

Definatly

THE MOST OBVIOUS CHOICE
Noob Saibot and Smoke cos i think they'd make a really original team.......

Cyrax & Sektor

Scorpion & Sub-Zero

Noob Saibot & Smoke

Reptile & Shang Tsung

Basically, characters that seem to have some sort of relation story wise.

Sonya + Jax
Sonya + Kano
Jax + Kano
Jax + Cyrax
Sonya + Cyrax
Kano + Cyrax

Are we related or just have a sibling rivalry? Liu Kang + Kung Lao
You are food! Baraka+ Reptile
Domestic Violence? Baraka+ Mileena
Hail Storm? Sub-zero+ Rain

PS. I greatly enjoy this thread and hope all of these combos will be possible

how epic would:
Warning contains violence
raiden + shang tsung
VS
U look nice!
Reptile + baraka

V.S.

Mileena + Tanya(if shes in that is)

Then it would be

Mileena + Reptile
Smoke + Sektor
Kunglao + Sektor