If I am the importer and obviously biased, can I mention the ATC SCM20 active or passive should be on your "7 inch driver" list? It's a true stand mount. ATC does not use a transmission line or port to boost bass with the cabinet on the SCM20-its a sealed box, with the ideal 12dB per octave roll off from its usable limit (which is about 85Hz).
It should be discussed that bass needs a larger room to be heard. The science of Wavelengths need to be considered, because expecting true 32Hz means you need an 11 meter (or about 35 feet) room dimension to support wavelengths at 32Hz. Even if the speaker is capable and tries to produce it, it's longer than the room so it won't work out well! So some acoustics minded folks would say, measure your room, know how low the usable limit of your room is. Then work backwards to find a speaker that goes at least that low. Investing in bass you cannot hear will generate another Audiogon post ("my speaker says 50Hz but they have no bass in this room") . A 10x13 ft room can ideally support as low as 85Hz - hence the the SCM 20 at about 85Hz roll off is an ideal fit in this size space. With low frequency, the larger the room the better.
[it should also be added there are tricks using multiple subs at low level to force bass into a space smaller than the room dimensions technically allow. Sometimes 3 or 4 subs are needed. This is how we do it in a studio or home when a client has to have it, but this work around gets expensive and has its own flaws and limitations]
Brad