Depending on your taste, Eddie Jackson (Queensryche) uses a SansAmp rackmount unit and Geddy Lee uses a BBE Bass Preamp (not Sonic Maximizer). They have pretty meaty bass tone, so just for input sake.
Not that I'm suggesting either way, but Geddy doesn't even run amps onstage anymore. I'm sure you've seen the washer/dryer setup on his side of the stage in live videos lately. He does everything direct.
So, in the light of this, not that I'm saying "you should go for those guys' bass tones"...the question is do you really want a 400 lb rack or are you just going for what looks cool and all that. Now that I said that, I will say that I would probably have a huge rack as well...given that I use a Mesa Triaxis/Mesa 2:90/TCElectronic G-Major/Rack Tuner rig, it's not too much different.
Behringer has rack tuners for like $50 or something, I'm sure they work just fine. Otherwise, those new Korg stage tuners are small and discreet...small enough to stay out of the way but enough that you can actually see.
If you feel like you need a SansAmp on top of your Ampeg, it should be simply as a backup direct rig if your Ampeg goes tits up. Otherwise, your Ampeg should work fine.