Of course, everything depends on your budget, the BDI21 will get you in the ball park, the SansAmp will defintely give you options.
You could also maybe look at the Tech21 Bass Fly Rig, the v2.0 has both the BDDI and the VT Bass circuits, as well as a compressor, chorus, filter and a tuner. There was one for sale in the Effects section not too long ago.
If you want to go digital, there's the HX FX, which includes models of the BDDI, Darkglass, Pearce & Noble pre's, as well as a whole load of other effects.
You could look at picking up a Zoom B2 Four / B6 or and older B3n/B3.
The Boss ME or GT processors have loyal fans.