We have several electric upright bass options, and which you choose depends largely on your budget. As you can imagine, the most realistic sound comes from the most expensive instrument. But money's not the only factor -- one of the other options might actually be a better fit. Here's some food for thought:
The Dean Pace Contra is a nice entry-level Electric Upright Bass; like all the EUBs we sell, it has the appropriate scale, fingerboard curvature, and feel. It can be bowed, and the standard 3/4 size string length provides the appropriate "bloom" when played with upright technique. It can use most standard strings, and transports easily. It has a built-in preamp, which even includes a headphone jack and an auxiliary input, which you can use to input an MP3 player or other source for play-along practicing. It stands on a standard endpin and includes side bouts to allow you to address the instrument in a more "upright-like" way. It's a solid-body instrument, so it does lack a little of that natural "open" sound, but many players have used effects (like a reverb pedal with a very tight reverb program) to simulate that timbre.
NS Design makes several Electric Upright Basses. The designs are almost identical, but the more expensive models add features and a fit and finish that justifies their price differences. The NXT bass is a professional-grade instrument, with -- again -- proper scale length, fingerboard profile, bowability... but in a highly ergonomic and decidedly more modern design. Also a solid-body, it's beautifully made and highly portable. A free-standing tripod stand is offered with the bass, but other options are provided, including an endpin with a standoff to put the bass in a more "traditional" position and feel. They also make shoulder straps!
The NS Design CR-grade basses jump up in materials, build quality, and feature set. I often draw the comparison between a Fender® Precision Bass®, which is available in several grades; their "Standard" Mexican-made model is a bass used worldwide by professionals with no reservations - but if you pick up an American Standard or Deluxe model, you can feel the difference in the choice woods and the extra attention paid to the finer details. It's kind of like that. Plus, the CR models include upgraded stands and cases, and add electronics upgrades like active preamps and magnetic pickups.
A note on strings for the NS basses (and the Dean, while I'm at it). Here's my philosophy on the subject: The best any EUB could hope to achieve would be to sound like a double bass with a pickup on it. Since the NS basses are tightly constructed and are solid-body instruments, their habits lean towards a more electric sounding bass (more sustain, more string detail, that sort of thing.) Since Ned Steinberger never really intended for the bass to necessarily be a substitute for the "real" upright (but rather a "new class" of hybrid instrument between upright and electric), the stock strings (NS Electric "Contemporary") don't help; they're fairly un-upright-like in my opinion. In my experience, using strings which pull it towards a more URB-oriented sound (less sustain, a more blunt attack to notes, almost a gut-string-like vibe) will effectively counter-balance the electric nature of the bass.
Two strings which I have personally tried and found success with are the Pirastro Obligatos and the D'Addario Helicore Orchestra strings. Both have a darker, less defined tone which sounds great on my WAV4 (the earlier, Chinese-made version of the NXT, now discontinued in favor of the Czech-made NXT); and both strings fit the bass-guitar-sized tuning machines on the bass. I have the Helicore Orchestral strings on my personal bass and like them quite a bit; I've also strung up several customer's basses with the Obligatos.
Specific to the NS Basses, the "NS Electric Traditional" strings are essentially Helicore Orchestra strings that are sized to fit the NS basses, so those are a great choice, especially if you don't want to wrap the strings around the bottom of the bass (they're also about $15 cheaper than the full-length strings!)
Finally, the Eminence Bass is the closest relative to a true upright bass to our hands and ears. It was the first EUB that really caught Bob's attention, that he wanted to continue to play and enjoy -- it has the vibe, both literally and figuratively-- the vibrations of a truly acoustic instrument against the body, and the feel of a true double bass neck. It is constructed like a full size double bass, with a bass bar and sound post. It has a nicely crafted removable wooden bout to put the bass in the perfect playing position. And while the acoustic sound is not loud enough, unamplified, to perform with, it can be practiced without an amp, as the acoustic sound is quite pleasing but won't be transmitted throughout the house.
So, each bass has its strengths, and perhaps your best option is not necessarily the most expensive, depending on what your needs are. If you have any questions not answered here, feel free to contact us with your specific questions.