First: There is a Job Template Plugin, I think as part of Jenkins Enterprise
Possible downsides of your approach:
* Job history: In your main build Job, you will have a mixed up history
of the different configurations, which makes reading anything out of it
harder.
* Pipleline: You'll have only one pipleine for the different
configurations -- it may (or not) de desirable to have multiple.
cheers,
Martin