It can be a labor of love and its not actually Converting, its doing what GURPS does best Taking the Premises and Making the system fit it.
Although, with all the awesome mech, weapons, and futuristic warrior art I don't see why someone just get make their own kitching sink setting.
Kitchen Sink Settings are an exercise of Logic and Consistency. State the Parameters and Premises than edit everything to fit these key fundamental ideas.
Addressing all the Hard Science Consequences making Earth an Inter-dimensional (feel free to call your setting any of the following) Crossroad, Nexus, Junction, Impasse, Intersection, etc. in the middle of a Hight tech yet unusually Conventional War can be summed up in a one page proposal or spiel.
I recommend GURPS Action and Dungeon Fantasy to build Epic Templates.
Since Space and Time is Warped you can expand the scale and geographic features of the map equal to how your Airship or Hover transport take Days to cross vast stretches. You can actually have a fire-fly aspect going on, and just throw in Hollywood Astro Physics to plug the gap.
So Crossing Boundaries and Planes of existence might take Days. Planes of existence are in all 3 dimensions, requiring to flight up to hit Land, or underground to find another world, or underwater to etc... Several Dimensions might exist side by side and travelling a few meters over ground may lead you to the wrong dimension.
Then there could be mid ways and land between lands.
of course in this kind of setting, to magic and the supernatural has to be either scaled against technology or explained. The bottom line is not to make things too complicated when being mixed. Again, fix the premise so that when people start putting two and two together your setting won't implode.
Kitchen sink settings are too much work alone. They can be awesome, even from my kill-joy point of view but the work involved is massive. although come to think of it, they should make the best MMOs.
As something so scattered, such an MMO setting would need a TON of vision and not just an aesthetic but awesome organizing and consensus building skills.