Another literal meaning of 'Gudakesha' is 'he of the curly hair':
If you notice the Ganguli translation of The Mahabharata at sacred-texts.com, he seems undecided about how he should translate the word 'Gudakesha' initially as it's evident from this line of Adi Parva:
"Vaisampayana said, 'When the heroes of the Vrishni race began to speak repeatedly in this strain, Vasudeva uttered these words pregnant with deep import and consistent with true morality. Gudakesa (the conqueror of sleep or he of the curly hair), by what he hath done, hath not insulted our family. He hath without doubt, rather enhanced our respect. Partha knoweth that we of the Satwata race are never mercenary. The son of Pandu also regardeth a self-choice as doubtful in its results. Who also would approve of ...
However, at most other places, he went with 'the curly hair' meaning of the word, including BG 10.20 you quoted in your question:
"The Holy One said, --
'Well, unto thee I will declare my divine perfections, by means of the principal ones (among them), O chief of the Kurus, for there is no end to the extent of my (perfections).
I am the soul, O thou of curly hair, seated in the heart of every being, I am the beginning, and the middle, and the end also of all beings...
Also, in Udyoga Parva, while advising Duryodhana to mend his ways, Bhishma refers to Arjuna as "Partha, of eyes like lotus-petals, and curly hair...":
And let that foremost of smiters, Bhima, possessed of leonine shoulders and thighs round, and long, and mighty arms, embrace thee. And then let that son of Kunti, Dhananjaya, called also Partha, of eyes like lotus-petals, and curly hair and conch-like neck salute thee respectfully. Then let those tigers among men, the twin Aswins, unrivalled on earth for beauty, wait on thee with affection and reverence as on their preceptor.
Another translation available at IndianScriptures.com also translates the above almost exactly:
Later on, in Aswamedha Parva, Ganguli also footnotes that:
"Vaisampayana said, 'The heroic son of Sakuni, who was a mighty car-warrior among the Gandharas, accompanied by a large force, proceeded against the Kuru hero of curly hair.1
144:1: The etymology of Gudakesa as the lord of Gudaka or sleep, is fanciful.
Within The Mahabharata, if there was any clear evidence of Arjuna being called Gudakesha for having conquered sleep, I'm sure Ganguli would have went with that meaning in his translation.
Also, if Arjuna was especially proud of the fact that he had conquered sleep, I'm sure he too would have recited it as one of his names in his introduction to Uttara; but then he doesn't:
"Arjuna said, 'I will, O son of Virata, tell thee my ten names. Listen thou and compare them with what thou hadst heard before. Listen to them with close attention and concentrated mind. They are:
So given that, to answer your second question:
Are there any more Gudakesha people in this world?
Yes, in millions! :)
EDIT: Winthrop Sargeant also translates Gudakesha as "the Thick Haired One"