I figure someday some other poor schmuck will be trying to figure this out, so I'll just append the next thing that person is likely to trip over, since I did.
In order to extend the query to match multiple feature/settings, I needed a separate feature and setting in the select.
Code:
select distinct p from
Printer p, NetworkFeature f, Setting s, CopyFeature f2, Setting s2
where
(p.features['NetworkFeature'] = f and f.settings['contactName'] = s and s.value = 'Nick Mudd')
and
(p.features['CopyFeature'] = f2 and f2.settings['duplex'] = s2 and s2.value = 'Off')
I really feel like I earned my salary today :-)
-Jeff