IMHO a Presso would be too cumbersome, both in making 1 reasonably sized cup, as well as cleaning...
but i do not have enough hard-ware knowledge to recommend you a machine, DrD...
i think it would also depend on the coffee making skills of the staff... would they want to watch the extractionlike a hawk to be able to cut it before blonding, or would they want a volumetric?
would they want to texture their own milk or have a super auto do the lot?
what is your budget?
but i am sure one of the sites sponsors will find you something !!