GregTech was intentionally excluded from Unleashed and got its own pack because GregTech is a conversion mod that changes Minecraft from the ground up, instead of just adding to it as 99% of the other mods do. Too many other mods make assumptions based on vanilla that are no longer true when GregTech is present, and therefore they can't work as intended. In return, the presence of other mods removes and waters down the strict progression tree that GregTech aims to achieve.
As a result it was decided to not include GregTech in the main "all the mods we could possibly think of" pack, which became Unleashed. Instead it got its own pack, with mods chosen specifically to work well with it. That pack is Unhingend.
So, no - you will never see a version of Unleashed with GregTech, I'm afraid. Regardless of update policy.