I've asked this before, but here is a different take on it.
Can you extend Sellacious to include a donation or subscription system - So at it's most basic level can have a donate or subscribe button, giving access to users content, or just donating to users - synced with ES profiles, stream etc. no where on wordpress, joomla or any other CMS I can find this feature, maybe because no one wants it, but i think its a great monetization system and i think it shouldn't be too hard to extend what you have to do this.
So eg store owner creates content, for free on ES, also sells products via multi-vendor Sellacious (synced with ES). The free content, draws people and users in, and some may prefer the system of donating as they go, rather than paying per product, or video download. Site admin takes commission on both - everyone happy.