Assuming they stay in the same division (for instance, not including if Silva vacates the belt to drop down).
BW: Dominick Cruz
FW: Jose Aldo
LW: Benson Henderson
WW: Georges St. Pierre
MW: Anderson Silva
LHW: Jon Jones
HW: Junior dos Santos
Most of these guys seem kind of unbeatable (excluding maybe Ben Henderson, who is an incredible fighter in his own right).
My order, Ben Henderson, Junior dos Santos, Jose Aldo, Dominick Cruz, Anderson Silva, Georges St Pierre, Jon Jones.
interesting thread.
bendo, cruz, jds, anderson, gsp, aldo, jones
Bendo Cruz jds gsp Aldo jones Anderson 
gsp, cruz, jds, bendo, aldo, anderson, jones
Jones to Hendo, Cruz, GSP to Condit, JDS to the Reem
Jones(To Hendo), JDS (think he loses to Overeem), Bendo (probably to Nate), Cruz (to Barao), GSP (to one of Nick Diaz or Rory), Anderson (I think he retires with the belt), Aldo (dont' see anyone beating him in the next couple of years at least.)
7 fighters, all ducking eachother
-the ug
Cruz, Bendo, JDS, Anderson, Aldo, GSP, Jones
Bendo
Cruz
JDS
^^Only ones I see potentially losing to current fighters in their weight class^^
GSP
Anderson- Probably retires with belt, though.
Aldo
Bones
Bendo, JDS, Cruz, GSP, Bones (though I think JBJ will get it back and be more dominate than ever).
Aldo will vacate his belt and move up to 55 before he loses it. Andy will retire as champ.
Bendo, Jones, JDS, Aldo, GSP, Anderson, Cruz
Actually, the more I think about it, the more I think Aldo could lose in the next year if Edgar moves down.
Methinks GSP loses his next fight. He is pretty much going to have a 2 year layoff and then half to fight the toughest guy in the division without any warmup fight. It is tough enough just having a warmup fight in the UFC after a layoff.
I don't know of a champ who has done this. Too be honest, I am too lazy to look. I just think it would be really difficult.
bendo/jones/JDS/cruz/silva/aldo/gsp
JoeLauzonPutHisCrotchInMyFaceAndILovedIt - bendo/jones/JDS/cruz/silva/aldo/gsp
lolwut
I'll say gsp and Cruz. 
DamnSevern - 7 fighters, all ducking eachother
-the ug
Cruz, Bendo, JDS, Anderson, Aldo, GSP, Jones
GSP, Henderson, Cruz, JDS, Jones, Aldo, Silva.
GSP hasn't fought in like 6 years and doesn't take well to getting hit in the face, LW division too stacked, Cruz cause he's a dork, JDS cause I fear he's too one dimensional (yes I said it), Jones cause he thinks he knows everything already, Aldo is a demon and Silva retires undefeated in ufc
OneTesticledMoneyLaunderer -JoeLauzonPutHisCrotchInMyFaceAndILovedIt - bendo/jones/JDS/cruz/silva/aldo/gsp
lolwut
what dont you understan fren? the first 3 will loose their next match up. the others will game plan properly and keep defending.