I'm down for this. The problem with making Voltron is that it will require a GOO-GOBBLE of resources which will reward just a few people who get to pilot it? Perhaps a better model would be Vehicle Voltron, or more feasibly, a Bipedal Capital Ship that involves a number of characters. After all, I think the FTL drives and energy sources require maintenance during conflict, which means that making a bipedal mech will reduce Voltron to a glorified fighter, a frigate at best, not a world class powerhouse, since it has nothing to generate that kind of power.
Clever engineering might allow someone to make a 5-person ship with the same offensive capabilities as a large capital ship, and then further to implement that as bipedal mech, and then further to implement that as five separate fully operational fighters that can link together and function as a whole. I am, in short, a huge, huge fan of this idea, and would be fully invested in making it come together, but even then, you have to ask, what kind of organization or economy would support it? Perhaps have a city, perhaps purported as a safe haven for newbies that has Voltron as a planetary defender. Of course, then it's not so much Voltron as Power Rangers, which, imho, is also awesome, sue me.
Honestly though, I'd love to see something like this. Because really, as soon as you see someone's Capital ship unfold into a giant mech, you'd flip all the way the F out, because geez... what?
Alternately you could create a mech Industry, selling blueprints, but then you'd need to create a market for mechs, which means something that ships cannot do. Land Warfare is great, but also perhaps consider Mech Arenas, where people bring their best bots and fight to the finish in a Colosseum. That kind of thing could also work as a great economy base for a Voltron. Having a giant badarse mech be that organization's defense kinda adds to the spectacle and popularity.
Let's do it!