Hmm. The one thing that stuck out to me was "millions of promotions" - how are you quantifying that?
Are you developing/looking to develop this yourself internally as a retailer, or are you building this out on behalf of a retailer? Some of the other bits you've mentioned certainly sound complex (although this might be how you've approached these combinations of options and products), but not outside the realm of a Spree/Solidus or Workarea style implementation.
Are you developing/looking to develop this yourself internally as a retailer, or are you building this out on behalf of a retailer? Some of the other bits you've mentioned certainly sound complex (although this might be how you've approached these combinations of options and products), but not outside the realm of a Spree/Solidus or Workarea style implementation.