For decent answers, try being sparse on what the thing your testing is instead of how you need to test
What kinds of peripherals are you testing, is it high side switches, low side switches (for the resistive stuff), ok if so what resistance or current ranges do you need to cater for, and for how long.
If its digital IO, what data and edge rates do you need to cater for, is it just a repeating sequence, or does it need to be generated live?
Are the tests sequencial, or all at once.
How many unique analog measurements do you need to cater for and to what resolution, e.g. could a window comparitor with a dual dac get you by.
Etc.
This leaves us with no idea what you magical black box is, but would give the amount of detail required to assist yoy.