So could Forge ever make a green lantern power ring, ultimate nulifier, an infinity gauntlet, or a machine that makes omega beams?  I wonder if there's any kind of limit to his mutant power??

I don't think he could make a Green Lantern Ring or Infinity Gauntlet only because he doesn't have the cosmic energy to power them. As for the Ultimate Nulifier I don't see why not.

The infinity gauntlet is not a machine or device (as far as I know).  Omega beams exist in an entirely different universe, as do green lantern rings, so the ability to make them specifically is questionable.  As far as the technology in the ring I would imagine he could (hard light constructs, artificially intelligent database, communicator, etc don't seem outside of his range, the problem would probably be miniaturizing the technology to the size of the ring).  Omega beams I don't know.  As far as the ultimate nulifier is concerned I would doubt it.  If he were an omega level mutant perhaps, otherwise I would doubt it.

Well I certainly thank you both for your input!  I didn't even think about the gems not being a machine.  Idiot.  These are the thoughts that go through my mind.

Speaking of Forge, why isn't he used more?
Back in the eighties he made a fool-proof skrull-detecting machine. Should come in handy these days.

Well pretty much all the explanations presented above for the GL ring, Infinity Gauntlet and machine to make omega beams seem sound.
What I wanted to answer was the question of Forge duplicating the Ultimate Nullifier.

Forges power has been described as a superhuman talent for inventing mechanical devices.
However it has been stated that this talent for invention does not mean that he is a greater inventor than geniuses such as Reed Richards, Victor von Doom, or Anthony Stark, none of whom owe their talent for invention to mutation.
These other invnetive genius's must for the most part consciously work out the theoretical principles behind the invention and then the design of the invention itself through a series of logical steps. In Forge's case, however, many of these logical steps would be worked out by his subconscious mind. Hence, Forge himself might not be entirely aware of exactly how he figured out how to create an invention of his.

Forge in the past has invented a neutralizer gun that could suppress superhuman mutant abilities and a device that could detect and combat the shape-changing alien Dire Wraiths. This scanner device could detect the presence of superhumanly powerful mutants and extraterrestrials in its wielder's vicinity, and could even specifically differentiate between Dire Wraiths and other aliens.

Using this example and the fact that he would appear to not be able to create devices beyond those of Reed Richards, I don't think that he could create the Ultimate Nullifier as is is an object that
1. May not be a simple mechanical device (it has be alledged to be an aspect of Galactus)
2. If it is a mechanical device, it would likely be beyond Forges (or even Reed Richards) ability to understand (conciously or subconciously) it's workings, as it has the capacity to destroy 'objects' such as Timelines or even Universes, that require a greater intellect than Forges to fully understand (needing an intellect like Galactus's).

"Well pretty much all the explanations presented above for the GL ring, Infinity Gauntlet and machine to make omega beams seem sound.
What I wanted to answer was the question of Forge duplicating the Ultimate Nullifier.

Forges power has been described as a superhuman talent for inventing mechanical devices.
However it has been stated that this talent for invention does not mean that he is a greater inventor than geniuses such as Reed Richards, Victor von Doom, or Anthony Stark, none of whom owe their talent for invention to mutation.
These other invnetive genius's must for the most part consciously work out the theoretical principles behind the invention and then the design of the invention itself through a series of logical steps. In Forge's case, however, many of these logical steps would be worked out by his subconscious mind. Hence, Forge himself might not be entirely aware of exactly how he figured out how to create an invention of his.

Forge in the past has invented a neutralizer gun that could suppress superhuman mutant abilities and a device that could detect and combat the shape-changing alien Dire Wraiths. This scanner device could detect the presence of superhumanly powerful mutants and extraterrestrials in its wielder's vicinity, and could even specifically differentiate between Dire Wraiths and other aliens.

Using this example and the fact that he would appear to not be able to create devices beyond those of Reed Richards, I don't think that he could create the Ultimate Nullifier as is is an object that
1. May not be a simple mechanical device (it has be alledged to be an aspect of Galactus)
2. If it is a mechanical device, it would likely be beyond Forges (or even Reed Richards) ability to understand (conciously or subconciously) it's workings, as it has the capacity to destroy 'objects' such as Timelines or even Universes, that require a greater intellect than Forges to fully understand (needing an intellect like Galactus's)."

Whoah... You should make entries for the Official Handbook of the Marvel Universe..."

I don't think he could make a Green Lantern Ring or Infinity Gauntlet only because he doesn't have the cosmic energy to power them. As for the Ultimate Nulifier I don't see why not.