Just me rambling about some crazy and somewhat "unrealistic" methods of how to make the most OP Nintaijutsu focused Naruto I can. Not to be taken seriously. Just an imagination exercise, if you will. While not exactly a Challenge, you can write about it, if you want. If you do, let me know so I can read your fic and tell other people about it.
Disclaimer: I do not own Naruto.
Before anything else, I'd change Minato and Kushina a bit. Kushina would still be an Uzumaki, but she would also have the Boil Release Kekkei Genkai. You know how Han, the Gobi's Jinchūriki, is able to use Boil Release to boost his Taijutsu? Naruto would be able to do that. Minato would also get a power up, as I'd make him a member of the Kaguya Clan. While the Shukotsumyaku is an awesome Kekkei Genkai, what I am looking at here is the insane regen factor its users get and stronger-than-steel bones. The regen part is more implied than explained; Kimimaro was able to heal the wounds caused by extracting his bones in seconds and regenerate his bones in less time than that.
For what is coming up, Naruto would need the combination of "steel" bones, Uzumaki Clan's vitality and regen and Kaguya Clan's regen in order to survive. Of course, he would become Kurama's Jinchūriki, which would help A LOT too.
When we talk about Taijutsu, one of the first things that comes to mind are the Eight Gates. Naturally, Naruto would train to open them and, eventually, be able to use the last one without dying. To do so, the most important tool he would need is the Byakugō Seal. This has the bonus benefit of Naruto learning Iryō Ninjutsu and Tsunade's Super Strength, which would also boost his Taijutsu. Having perfect Chakra Control is nice too lol.
While not a Taijutsu technique, I'd also have Naruto learn the Shadow Clone Jutsu, if only to help him learn everything else faster.
Naruto would also be a Toad Summoner, which would allow him to become a Sage (which by itself is another Taijutsu booster) and use the Frog Kumite. The Frog Kumite is said to be the ultimate Taijutsu Style, with no flaws to both its offense and defense. While having the perfect style is awesome, the Frog Kumite has one flaw; if I am not mistaken, it can only be used on its fullest extent while in Sage Mode. And there are scenarios where it would be difficult or impossible for Naruto to activate the Sage Mode.
To walk around this wall, Naruto would also be born the Mind's Eye of the Kagura. Sure, it is not the same as Sage Mode, but the Kagura Shingan is said to be the strongest sensing ability besides Sage Mode. In terms of sensory capabilities, I believe the Kagura Shingan to be stronger than the Byakugan and Sharingan combined. Speaking of the Dōjutsus, why didn't I give Naruto one (or both)? Wouldn't they also improve his Taijutsu? Yeah, they would. The Byakugan (and the Jūken by extension) in particular would be a good alternative for whenever Naruto doesn't have Sage Mode active. The thing is, I didn't want Naruto to have a Dōjutsu. Simple as that lol. Besides, the Kagura Shingan might not be as fleshy or overall powerful, but I think it goes better with the theme I'm going for.
As I mentioned before, Naruto would be able to use Boil Release to boost his Taijutsu capabilities (I believe it is called Boil Release: Unrivaled Strength). But he would have another Elemental Jutsu to enhance himself with; Raiton: Chakra Mode. You know, the jutsu that made the Third Raikage almost impossible to be harmed and gave him insane speed? That one. It would be cool if Naruto managed to do a version of it with Black Lightning, but I'm still not sure about it. All I know about Black Lightning is that it is stronger than normal Raiton. But would it be possible to make a Chakra Mode out of it? Ha, who am I kidding? I'd make it possible!
I think that's all… Maybe I should compile everything into a "spreadsheet". Let me know if you think about anything that could be added. Of course, I'd give Naruto these abilities in a "realistic" pace, if I were to write a fic about it:
Naruto Uzumaki
Clan: Uzumaki and Kaguya;
Kekkei Genkai: Shukotsumyaku, Kagura Shingan and Futton (Boil Release);
Elemental Affinities: Raiton, Katon, Suiton and Futton;
Taijutsu Style: Frog Kumite
Jutsus: Eight Gates of Chakra; Tsunade's Super Strength, Byakugō Seal, Summoning, Sage Mode, Kurama Chakra Cloak, Raiton: (Black) Chakra Mode, Futton: Unrivaled Strength, Shadow Clones and many others;
Notes: Kyūbi's Jinchūriki, unmatched Chakra Reserves/Life Force/Constitution and Regen, perfect Chakra Control, Nintaijutsu and Iryō Ninjutsu master.