Different content fields per client

It would be nice to be able to specify fields to each 'client' so that you add fields for serial. no, version. no and such for the 'tech support' tickets while the tickets associated with 'information' has different fields associated with it.

My first thought was to implement a way of getting STS to support different content types, this however seems hard to integrate and would probably mean a big change to the way the module works today.

My next thought was to make a custom module that would integrate with STS and the default content type. The way I picture it working is like this:

You add all the fields you want to be able to choose from to the support_ticket content type. One would then make the custom module do 2 alter_form calls where the first call would add checkboxes/radio buttons to each client so that you can choose to configure the client with extra fields.

The other alter_form would be for the display where it decides what fields to display based on what fields are 'activated' in the client settings.

What are your thoughts on this?