You may need to get your coding hands a bit dirty for displaying the different price comparisons within your theme, but we used CS-Cart with great success in the past on a wholesale-products site.
- Visitor Pricing (Non logged in users)
- Members Only Pricing (Must be logged in to even SEE prices)
- Group pricing options (Add a registered member to a specific group, for rate pricing)
The options were pretty wide... and just to be fair, I think several carts all have this functionality built in now, including freebies. CS Cart is not a free solution.
Disclaimer - no affiliation to CS cart whatsoever, just a satisfied past user.