I did see Jaco one time, but the best jazz electric bassist I've seen in my opinion is Jamaaladeen Tacuma.
Others I've enjoyed that come to mind are Albert McDowell (with Ornette), Gerald Veasley (with John Blake, McCoy Tyner and with Joe Zawinul), Mark Egan (with the Miles Evans Orchestra), John Lee (with Dizzy and with McCoy Tyner), Bruce Johnson (Ronald Shannon Jackson), Melvin Gibbs (Ronald Shannon Jackson and Oliver Lake), and Richard Bona (Mike Stern). Also, Tyrone Brown (who plays a hybrid) (with Max Roach and Odean Pope).