Okay, Me and My friends have tested this out in Low Platinum and it works like 90% of the Time. The Startegy depends mostly on Stone Walling and Snow Balling.

Let me Explain, Instead of Having the typical 1 mid lane, 1 top lane, a duo bot lane(ADC and Support} and a jungler. (FYI, This Strategy can still work with this set-up, its just that me and my friends feel more comfortable with the latter). we go with a duo top lane(one is a Mobile Assassin), duo bot lane(Another Mobile Assassin) and a midlaner.

Champions Required

- 3 Champions good a wave-clearing and Anti-sieging (Tower Defender Champions)

- 2 Mobile Assassins

In Most of our Game, we were using Anivia(Bot Lane), Taliyah(Mid lane), and GangPlank(Top Lane) as our defenders. We also opted using Brand Instead of Taliyah due to the high Instant burst damage to her kit and replacing it with one who had a somewhat controlled burst damage due to combo changes, it works its just our mid laner was not comfortable using Brand.The Defenders do just that, they Do not push at all they keep their waves at a distance from the towers without going too far to get ganked while freezing the lane. and if they get into a little trouble they have the tower close to them and their wave clears ready. They will usually get the most farm but they have an even more important job and thats what we call Baby sitting. 

In this strategy, the Biggest weaknesses are the Killers, if they get caught if they tunnel vision too much, and the Defenders get overwhelmed its basically game over thats why in the pre-game i already tell them if they are even remotely close to the tower immediately escape. so for the Assassins we chose a variety of them testing Most if not all of them out in game so he are our findings :D

LeBlanc - somewhat Perfect for this Team comp she is not only hard to kill but snow balls very hard and is quiet fast in roaming and does not need much help from the Defenders with her burst potential.

Akali - The Baby sitters need to watch over her pre-level 6. we usually have to switch the lanes of Taliyah and Akali when the bot or top match-ups are too hard for her. Vice-versa if the mid lane is too hard for her. She snowballs quite hard once she gets the gunblade and is level 6. as long as the defenders are able to baby sit her it would be fine. Anivia does well in protecting her with walls, stuns and general nuking potential.

Katarina - Same as Akali, pre-level 6 is kinda a bust but the Defenders work well in defending plus she has that long range poke with her so alls good in the world. we did a match with her and akali in one team. we had to switch the lane match-ups quiet a bit with Taliyah and Katarina on Top Lane, Anivia and Akali on Bot lane and a Gangplank Mid Lane. Surprisingly worked well enough.

Fizz - His a a little **it, always has been always will be. once he snowballs, he snowballs hard. we could literally give him a solo lane if he wanted but we opted to keep everything just as is. meaning the Anivia was in the bushes with a red trinket waiting for a perfect chance to catch people off-guard.

Ekko - still OP AP ekko is even more OP. so much damage scaling for a utility assassin. we have checked and it works. his roaming is quite good even pre-level 6 and he shines even more 

Kassadin - Ummm.. how do i say this... we have had 1 game where he became a monster/beast but that was against an AP top match-up he was basically useless if he didnt snowball. Gangplank set-up most if not all of the kills for him. of course his still that legendary killer from before its just WAY WAY WAY WAY WAY Harder to get there. but once his arrived his as oppressive as ever. we had him get an Ancient Coin to max it while he was wave-clearing and getting kills and if the minions got too close to the tower well GP had all the money.

Shaco - Leave him in the Jungle, have the top laner start defending. that all i need to say.

Rengar - this was an amusing one for us, pre- six was hard don't get me wrong but Anivia and Rangar on top lane with rengar always waiting for that stun before jumping on them was just hilarious especially when they don't learn from it.

Kha'zix /Diana/Ahri/Talon/Zed/Nocturne - these guys are just like Leblanc, no problem whatsoever in snowballing,Wave Clear was definitely not a problem roaming was easy for them and with the enemy most if not all the time at our tower doors it made it easy for them to off one or two enemies. the defenders always being ready when theres a gank. 

I know with the Incoming Assassins Rework this strategy could become mute but they can be changing all of them xD. but i wanted to share it. there are big weaknesses to this strategy though. one of them being a lane bully bot lane match-up. Good thing Ashe and Jhin are in meta right now and not someone like Caitlyn. We usually ban those type of match ups anyway. Blitz, Leona, Braum, Thresh and the like is not something you like seeing. we get lucky with the picks of Heal/Shield supports being in-meta such as the Kog'maw/Lulu match -up is quite easy or the Soraka/Sona/Janna suppports.

An All Tank team can also pack a punch if you don't know what your doing,

This strategy really depends on the assassins to relieve pressure on lanes and roaming around getting kills. the moment that a defender gets over-whelmed then thats a problem.

Just sharing Hope you like the idea. its basically towerguards roaming the walls going from tower to tower. hope you like it. but dont try it on ranked solo queue unless you have a good team of friends that know what their doing. I usually have one and I love them for keeping me and helping my "Creative" ideas such as this come to life and testing it out :D