The configuration of available resources is located in the jenkins system configuration tab.
In case of a high amount of resources to administrate, this is blowing up this tab.
Gues a solution, where to save that resource informations in a configuration file and load that file on the jenkins system configuration tab would be a nice benifit.
An further anhancement could be to load the resources configuration file along with the job configuration. This could provide the benefit to have different configurations for different projects on one jenkins instance.
Having configurations in files also improves the possibility to make jobs reproduceable. The configuration files could be provided by an SCM-system along with the rather source code and gives an answer to the question, what external resources must be available to run that job...