I love making bass soloes, as long and as electic as my music can be.
Like, AznBassist said, the band has to keep the energy while the bassist solos, because once the groove stops, you're in deep shi!t unless your rhythm section is great enough to cover for you.
Or invest in a really good phrase sampler, lay down a phat groove, and then solo over it.
What if you ask your guitarist to let you experiment. Tell him to pretend to be the rhythm guy, and let you take over lead. See how that works.