Shaco: Jungle , sustain, D.P.S.,
Rumble: Solo mid, crowd control, AP carry
Mundo: Solo top, crowd control, tank,
Teemo: Duo bottom, map control, ranged ap carry
Renekton: Duo bottom, harass, support tank

The main idea of this build is to provide survive ability, chasing ability, damage, tower diving ability. And able to deal large amount of damage even under crowd control like Morgana + Amumu double ultimate, if timed perfectly, just by standing by with 4 "Sunfire capes" can take a few kills from enemy team.

To fully take advantage of Shaco's ultimate "Hallucinate" since you get double of everything on him when clone is activated, we can double the magic damage of "Sunfire Cap", "Tiamat". And if you have trouble in early game, doubling the defense buffs from "Aegis of the Legion" is also good for team fights.

Typical item build to maximize the slows and damage over time, but using the gold/per runes, can help rumble come back from a bad early game or excel even faster when game is going well. Rumble is a kind of champion that can demolish over leveled enemies with gold due to his amazing surviving skills. Even when he is 4-5 level under, his ultimate "The Equalizer" and "E" skill "Electro-harpoom" can benefit the team due to the long range slow.

If you are having a good early game with Dr. Mundo, next time try buying "Rylai's Crystal Scepter" before "Warmog's Armor", you will know what I mean.

A cool-down reduction plus attack speed ability power build Teemo can maximize his ultimate "Noxious Trap" as well as his "E" skill "Toxic Shot". His job would be to provide map control and escape routes for teammates when being chased down, while he can still fight in team battles outside the nuke zones and plant "Noxious Traps" in case for a escape. Teemo should always have one "Noxious Trap" ready at all times, so only plant "Noxious Traps" when he has 2 or more available.

Without mana consumption, Renekton can reach full trolness with cool-down reduction from "Ionian Boots of Lucidty". Supporting at bottome lane,, Renekton must save his abilities to make sure his carry survives, and save his "E" skill "Slice And Dice" and "W" skill "Ruthless Predator" for kill securing.
Because of the cool-down reduction you have with this build, you can also use your ultimate "Dominus" almost every minute, taking advantage of it's area of effect granting you kills and lots of assists, "Sword Of The Occult" will stack very quickly.
Also, Renekton can perform a double heal bait, with his ultimate along with the summoner heal, can take a large amount of enemy skills and damage, heal himself and dash out with "Slice And Dice" easily.