Cylons do have some forms of rank, but mainly this is just an honorific amongst Centurions. As stated elsewhere, Silver Centurions use Flight Leader (sometimes also called Patrol Leader) and Group Leader ranks. Ranks are not displayed visably on a Cylon, with the Information Network available to them, there is no need, all Cylons will automatically have rank and status information available to them.
However, the Cylons do have status and vie for position amongst themselves. This is not a visible rank thing, but political and generally means that the higher status Cylons will get more chances for glory and promotion.
The Cylons do have a special order though - Warriors of the Elite Class. This is a sure-fire way of getting promoted and advancing up through the ranks with glory and status.
These Cylons wear a black sash around their person, and represent a Cylon that has done something outstanding, or denotes a very capable Cylon. Cylons that show these talents walk a fine line though. While the Cylon Empire recognises the fact that some Cylons are unique and therefore more capable than others, it also recognises the fact that Cylons have engineered brains and circuits, and a Cylon who continuously displays talent outside their programming may be malfunctioning or have been tampered with. Or, it may be a genuine talent that the Cylon has, in which case, the Cylon race has to determine whether or not this is capable of being duplicated, and if this would be wise.
A Warrior of the Elite Class is of higher status than other Cylons of their own rank, and with this usually comes extra responsibility as well. Sometimes a Cylon may also be awarded additional rank (and brains) because of being distinguished, in which case, in their new rank, they may not wear the sash, but it will be recorded in their service record.
Funnily enough, Cylons who work their way up the ranks in this manner are not generally looked upon with favour, but instead with suspicion. Unless they reach IL series level, in which case this stigma is lost.
Drones: Drones can never achieve distinguished status, they lack the initiative and intelligence. If they were to do something extraordinary, they would be disassembled.
Citizens: Citizens find it hard to achieve Elite Class status, they lack most of the qualities needed to do something of note. If they do, then they will be allowed to wear the sash. However, citizens have a hard time of it. If they continue to do things of note, they will be watched to see if they are malfunctioning.
Silver Centurions: Like citizens, Silver Centurions find it hard to achieve Elite Class status, but they can do it. As a Silver Centurions life expectancy is so low, there is usually no chance of them being distinguished twice. But it does sometimes happen. Like citizens, Silver Centurions have to be careful. Because of their limited programming, they have as much chance of being dissembled as they have being awarded a second brain and being upgraded to Gold centurion status.
Gold Centurions: May be awarded the Elite Class sash with no problems. However, a First Centurion generally has no where to advance too. Occasionally they may be upgraded to IL series, but this is rare.
IL Series: The IL series have no problems with being awarded the sash, but like First Centurions, they also have no where to advance. IL series Cylons also have the problem in that because of their already unique qualities, it can be hard to decide what constitutes an noteworthy act, and with all the politicking that goes on with the IL series, they are always vying for position over each other.
One reason for this is that only a distinguished IL series Cylon may become awarded the rank of Imperious Leader.