Here is a short composition on the fretless bass alone. The bass is a Weller, a small German brand that sells its instruments on eBay for very reasonable prices, give them a check, my bass is very well made and can easily compete with superior brands.
The sound is direct from the instrument (no amps simulations or whatsoever) with reverb and delay.
Perhaps the central part could be more refined and well played… let me know what you think :)