Disclaimer: I don't own Naruto, I don't even own any copies of the anime or manga, so don't expect this to stay in canon.
Bigger is Better
Naruto was fighting Hyuuga Neji in the Chuunin Exam finals and his clones were getting their asses kicked and he was getting a killer headache as the memories of getting hit so many times downloaded into his brain.
"You see how futile your attempts at 'Quantity over Quality' are." Neji remarked loudly as he killed three more clones the had been charging from behind him. "This is further proof that you a Fated to Lose here."
Then Naruto had an epiphany and he yelled back "Well then lets try 'Bigger is Better'!"
------------ Flashback Start ---------------------
Naruto was in the forest reading about the Kage Bunshin no Jutsu from the Forbidden Scroll and saw some notes in the sidebar: "By exchanging the Monkey Seal for the Dragon Seal the variable for more or less chakra becomes size rather than quantity. This is more difficult to master because the strength of the clones muscles and bones must increase or decrease as well. Incorrect adjustment cause smaller clones to be clumsy and overjump until they get used to the differences, while larger clones will be weak, clumsy and prone to bone breakage. The math to figure this all out is beyond me, but some brainy chick once mentioned a 'Cube Square Rule' but no one else knows what she was talking about. Most people ignore this since the clone made can't be mistaken for you, but small clones are excellent for spying, and large clones are good for heavy labor."
'Bigger or smaller clones sounds cool.' Naruto though as he looked for other sidebar info about this nifty jutsu and found one written in a neat and feminine hand: "That idiot can't do math to save his life! The 'Cube Square Rule' applies to animal body shapes by size and explains why bugs don't need bones and can lift many times their body weight while having a low muscle ratio and why elephants have such huge bones and short, muscular legs. But since Kage Bunshin are chakra constructs instead of real muscle and bone you can adjust the muscle and bone strength in proportion to the adjustment in height to avoid clumsy or overloaded clones. So for a clones of double your height you spend double the chakra for Length, Width, Height, and Strength, or 16 times the chakra of a normal Kage Bunshin, so very few people have the chakra capacity to make combat giants without killing themselves in the attempt!"
Looking further down the scroll Naruto found a final note on the Kage Bunshin written in the messy hand once again: "Don't decrease the strength of smaller clones near as much as she says. Yeah, you end up clumsy and overjump if your not careful, but at least your muscles doesn't become weak as jello and you won't kill yourself with a damn papercut. On the flipside a giant should have skin like leather and muscles as hard as wood. Oh and if you havn't figured it out yet, when a clone disperses you get the memories of the clone, so killing a bunch at once will give you a headache. So don't strain your brain, kill one at a time!"
--------------- Flashback End ------------------------
'Lets see 10 feet tall 2, 4, 8, 16, I can do more than that. 20 feet tall 32, 64, 128, 256! I can do that! ... barely.' Naruto worked out in his head as he did the handsigns with one change and called out "KAIJU Kage Bunshin no Jutsu!"
There was a loud #Boomf!# and there stood a shadow clone of Naruto that stood over 20 feet tall, that looked down at Neji and said in a deep and load baritone voice "You think fate is going to help you now, Peewee?"
Kaiju-Naruto looked down at Neji, who looked all of 17 inches tall, and figured he shouldn't hit the little guy too hard or he'd kill him, especially since he wasn't just freakin' huge, he was also 4 times as strong and tough as before as well. That wasn't the only thing that he noticed either, the sand of the arena felt like thin shifting dust under his feet, so his footing wasn't very good as well.
Neji stared in shock at the humongous clone of Naruto in front of him and decided it was best to pop the clone before it got too close and went for his kunai as the giant charged him. Seeing a 20 foot tall, 3 ton Naruto coming at him at what must be 60 mph Neji started his spin and brought up the Kaiten just before being punted 30 feet back and into the wall by the side of Kaiju-Naruto's 3 foot long foot.
The giant clone watched his opponent's Kaiten fail when he hit the wall and dove forwards to pin Neji to the ground before he could recover, but almost flubbed it up because he wasn't falling fast enough, but then he realized that it takes longer to fall 20 feet than 5 feet and this was just another thing to get used to when he was a giant.
Neji was in a lot of pain as he pried himself out of his shallow impact crater and stumbled forwards just as an impact shook the ground in front of him and a set of 2 foot long hands grabbed him and pushed him face first into the sand and pressed down on him with what felt like a thousand pounds of weight.
The referee then yelled out "HOLD! The winner is Uzumaki Naruto!" Then running up to the clone he said "Don't disperse yourself! Take your hands off him gently and roll away while I get some medics in here." Then as the giant clone rolled away and exposed the defeated and squished looking Neji he yelled out "Get the medi-nins in here with a stretcher and a neck brace!"
This is likely to remain a one-shot, but if anyone wants to use this idea, feel free, just let me read it when your done.