modulair cloud

Why is there no modulair cloud?

What I mean is, why are there only complex infrastructures, or full blown enterprise applications available as Saas? As a small business I don't want to pay for those extreme systems (which I don't need), but I would like to take advantage of the possibilities of cloud computing.

Sure, Google Apps is a great place to start. It brings me office applications, communication (like mail, chat etc) and some other nice stuff and all that for free (or even more for a small fee). But if I want to go beyond that, I have a problem.

Let's say I would like to have some sort of lightweight CRM system. I only want to store contact information and share that across my company. I don't need the option to connect tasks, documents, opportunities and stuff like that. Google Apps doesn't give me that and most other providers give me (and charge me for) way too much!
Another example: I only want some system that can register the hours I and colleagues spend on a specific project, but without all the fancy project management features like planning, collaboration and so on.
What I would like to have is some kind of Saas á la carte, where I can combine separate modules into a complete, tailored back office system that gives me exactly what I need and nothing more.

As far as I know there is nothing like that yet on the market. If there is, please let me know!