In that case, how about if we do something along the lines of, Ash wishes so hard for his Gundam to show up and ~be there with him~ for the fight that he just kind of manifests a personal armor suit (human sized, worn on his limbs like a real suit of armor, etc) with similar capabilities to the Gundam he remembers? And then instead of being powered by a reactor or whatever battery source it uses, it runs on dream battery — thus, he can only use it for so long, and becomes more fatigued the longer he uses it?