Heres a system we came up with on the spur of the moment:
Research, instead of rolling a Knowledge check to know the fact instantly, usually requires spending time studying in some kind of library.
Researching a knowledge check allows you to take a 20, instead of rolling.
Time taken (in days) is figured as the DC of the check, subtract the skill level of the researcher, divide by 2.
A library will have a certain level of information available. A small temple library of a deity not reknowned for its love of literature may only be able to provide DC15-20 information, and a major library of a god of knowledge may be able to provide information of DC30 or more, and you can find what you are looking for if you can beat the DC.
Assists are allowed.