edit* Question came off wrong way.
there is absolutely no way anyone will be able to answer this without knowledge of the project. basically you are asking us how long will it take to build a building but I dont know how big, how many rooms, what materials, etc. Its just an impossible question to answer.
*edited
No one here is going to be able to answer that. Projects can take anywhere from a few weeks for something simple to months for larger projects. It all depends on so many different things, there's not an exact answer. As @diat150 said but even more. Besides what materials, how many rooms, floors, etc, you also need to know the experience of the people working on it, how many, etc.
What it really takes is experience/history before you can even come close to estimating how long it will take. There are things some programmers can knock out in a few hours that may take someone else days to do.
I think generally the answer [1] is going to be "weeks to months, but not days or years" and anything other than that is basically just a wild guess.
An experienced integration company which has made projects in the same business domain before is probably going to be faster than an overextended company working in an entirely new category. Beyond that, there's very few rules of thumb to even apply.
It is basically a rule [2] that every project, no matter how simple or cookie cutter in theory, will have at least one significant unforeseen roadblock of implementation. Take your most pessimistic estimation of the project timeline, double it, then accept that even that is probably wildly optimistic.
How long is a piece of string?