By Buckshot Comments
Majestic + Mjolnir: Always my go-to customization. I think it fits because Majestic is a warrior and Mjolnir is a warrior's weapon. It's a warrior king's weapon, and as was mentioned in the Thor movie (probably in the comics somewhere too, though I've never seen it) a hammer destroys and creates, and that's Majestic. The only real problem with it is that it's a hammer and Majestic likes swords, but he's used a mace before and I imagine he could use his forge to mix in some Kheran tech that makes his weapons capable of changing shape so he could turn it into a sword if he wanted to. The other thing is that it would give Majestic some power outside of his body. Majestic may be the best flying brick (I said it) but he's still a flying brick. The magic of the hammer makes him more than that, and I think he'd have fun learning all the things the hammer can do...and maybe coming up with new stuff. People forget, the Wildstorm universe is far more tech-heavy than magically inclined, and Majestic himself is a scientist, but he's not unfamiliar with magic.
Majestic + Nanoblood: This is the other option though. It only came to me recently. Majestic could have The Engineer's blood in him so he would always have on hand the materials needed to make whatever he wants, since he clearly has the intelligence to invent on the spot. I like the idea, but I don't think it has the same charm as Mjolnir.
Black Bolt + Green Ring: This comes from when I was thinking of Marvel characters that would be good GLs. I don't think there's a better answer than this going off straight willpower. I also like the idea that he'd be in a situation where his ring was taken and his enemies thought he was defeated and he reveals that he's never without a powerful weapon.
Cyborg Superman + Red Ring: C'mon, no brainer. Here's what I wrote about a year ago: Putting on a red ring generates a heart in his chest and his robot side allows him to control his rage making him the only Red Lantern other than Atrocitus that's in control of himself. His experience with Green and Yellow Lanterns allows him to generate constructs with the Red ring. He has the willpower and intelligence (don't forget that he was a brilliant scientist before all the craziness and every time he pulls some machine together it just shows how much of a builder he still is) to pull off more tricks than just flaming blood vomit. Plus, the ring keeping him alive will only drive his rage. He'll need to change his logo again though. It works though. The symbol of the Red Lanterns looks almost like an "H". Coincidence?
Gladiator + Cytorrak's Gem: This is basically because of his "I believe myself untouchable" line. I imagine him going into combat with a new battle slogan. "I believe myself unstoppable." Cuz really, he'd be perfect. Him actually being unstoppable would put his confidence through the roof, and for good reason. And the costume's helmet would cover his only potential weakness, a mental assault. That's really the biggest problem though, the costume. The body, though boring, isn't so much of a problem, but Kallark's mohawk is too cool to hide. Maybe he'd have new costume entirely, something more armor-like than what he normally wears (something closer to Majestic in World's End?) with some kind of helmet that lets his mohawk through to make him look like a real gladiator.
Sinestro + Speed Force: Probably overkill. Definitely a lot of yellow. I don't even know why other than I like both of these things and Sinestro's only real vulnerability is that he doesn't think as fast as the others I've created.
Silver Surfer: The problem with Silver Surfer is that he can do so much with his powers that it's hard to think of anything to give him that wouldn't put him on another level entirely. The only thing I feel like might even fit with his character is the Helmet of Nabu (not that I know much about it, mind) and that's just ridiculous.
Martian Manhunter: He has the same problem as Surfer. I don't really know what to add to him because he's already so versatile and his character doesn't really match with any other available thing.