A shop system that integrates into typo3 in the same spirit as tt_news.
Basically, define products as items in the backend, add plugins in the front end to display them.
Front End approach:
This shop system has no control over the page structure, you define it as you wish.
Also since the display of products is done through a simple plugin, you can position it as you want.
Multiple price lists are possible, using very simply the fe_user groups native to typo3.
Back End approach:
The Back end expectation was not to create a simple shop system, but something with rather an ERP (Entrerprise Resource Planning) approach. This includes logistics calculations, supplier & supplier orders management, reports, etc.