The big Soundcloud clip in my signature is such a recording. The bass is from my Ergo cello. I don't often go down onto the low Bb string, but use the F string quite a bit.
Indeed, there are compromises. The strings are quite slack, and the output can be quite hot for some preamps without good headroom. The low strings do not respond quickly to fast plucked passages due to their slackness. However, all notes down to Bb sound good. You'll note that the notes are heavy on the fundamental, unlike many bass guitars which are strong on the first harmonic at the octave.
The bass line below was recorded straight out of the cello into a Behringer ADI21, into Reaper, then compressed slightly with Kjaerhus Classic Compressor plugin.
It's just a scratch track for some music I'm going to record this fall with real musicians, in more complex form. Organs are programmed, the drums are Rayzoon Jamstix, an algorithmic drummer which can improvise slightly upon base rhythms. The horns are Garritan Jazz and Big Band samples, I didn't bother applying expressive MIDI parameters because it's just for scratch purposes.
The lead tracks are a second set of pickups i put into the Ergo cello, with the two pickups under the feet out of phase. The ones used for bass are a pair under the feet in phase. Picture a sandwich of two pickup elements under each foot, with neoprene washer between them, and you'll get an idea what I'm using. However, the stock Ergo pickups are comparable to the pair I'm using in my arrangement; I'm using Jesse's pickup elements.
I find a GHS short brite flat bass string, the E (.105) tunes up well to F, and might work as an E, even though the scale is much shorter. You can allow more slack in the string when you're not dealing with frets, though the bridge height might need to change. I also had a .105 gauge F string custom made by Octave4plus in 28" scale, it's also .105 gauge but is more flexible and pliant.
