yes ok so heres what we KNOW
There will be a main rank like in Reach this will increase with EXP. you earn exp in increments of 500 i believe and you get from games and such.
now will there be a 1-50? no
heres 1 more rank type thing thats in halo 4 they said something about branches in which contain 10 levels say you start at A you go A-0 - A-10 then when you reach the top you choose to reenlist say go to B they said this will be like you can choose to be a sniper specialist or a wheelman specialist quite confusing right now but we will see more later please feel free to ask questions in my topic! i will answer all questions thanks!

Really looking forward to getting a good rank, would like to see alot more customizable stuff

I'm really hoping it will be like Halo 3's ranking system.

I really hate the EXP system on reach.

"According to Frank O'Connor, the ranking system in Halo 4 won't be visible to other players and will only be visible to you. However, the game's matchmaking system will still take ranks into account when finding matches. There will be an experience and ranking system like Reach, but it'll be hidden to others to prevent cheating."

It'll be alot like the one in reach, but if I'm not mistaken noone else can see your rank.