Good solos?

Seems to me a rather difficult thing to help with as it is so nebulously defined. What is this supposed to do for your band?

Victor Wooten rightly noted that bass solos often suck because the bassist tries to be a lead guitarist and loses the groove/rhythm that is propelling the song. The song falters, the audience can't hold onto it and loses interest. The point is that a bassist needs to remember what it is they do for the band/song even when soloing.

I'd suggest taking a bass line you really enjoy playing and using that.

There's a section of a Duran Duran song - Mediterranea - that features the bass (I've called it the bass solo in the tab) but it is just a repeat of a part of the song but this time with the bass out front in the mix and no vocal. Retains the same groove/feel/rhythm of the song so it sits well with a listener. You could have a look at that perhaps.
Cheers.