Whether one wants or needs to hear the fundamental of a 32' low C is a personal thing. I sold my sub along with a church installation and am making do with a pair of Wharfedale full range 15" speakers that go down to about 25 Hz. I miss the Rythmik Audio F15HP but have not yet replaced it.
There are only a handful of subs that do a creditable job at 16 Hz and most of them are priced quite high. SRS has been mentioned and certainly Rythmik Audio makes some of the finest subs at prices beginning around $1500.
There is no need to find a 64-foot space to produce a "full wave". That is a resonant node that is best avoided if possible. The room size is NOT a factor except to the extent that it is much easier to produce 16 Hz in a smaller room. Large spaces such as sanctuaries require higher power subs, and usually more than one sub, to produce vibrations which can be felt.
Most of us need to get by with what we can afford and can settle for the very realistic harmonics of the lowest notes which are easily reproduced by more affordable subs.