well i seen this plugin for spoutcraft type of deal what it does is that when u log in you get a rank of citizen or whatever it is and then after an hour u get a new rank and after 370hrs of online time u get the title of titan [seperate from ranks like admins, gm, etc] im not sure what its called or i dont think its made but if it isnt someone kindly make this a plugin - AllSoloScarlett i.p. AfterDarkCraft.no-ip.org online during the morning day and evening, offline during the night.
OnTime can do this. After a certain amount of playing times can give players rewards, in your case ranks.
I may be able to help with configuring OnTime, but can you tell me what plugin you have for titles, or if you don't have one, which permissions plugin you use for ranks? Often the titles are associated with the rank.