Tech21 Sansamp BDDI Programmable or the Bass Fly rig V2 could be a good start if you need lots of different sounds.
The BDDI & VTDI Deluxe have been discontinued, but you may be able to find one second hand on here, or in an online market place of your choosing. Great, because they give you loads of different options.
There's always going down the digital modelling route with something like the Line6 PODGo, HX Stomp, Boss GT Core, Headrush, etc.