Is it possible to use unpatched E-Commerce and OpenResort simultaneously?

The site that I am currently developing both needs OpenResort and the ability to purchase site membership subscriptions.

After patching E-Commerce, the membership subscriptions are now bought through a Cart that is named Itinerary, (where it is marked together with resrevation date and number of nights to stay...) and by a button called Book instead of Checkout...

I tried separating the ecommerce modules by drupal multisites but this failed numerous times as soon as I tried to share database tables (which is necessary for the user activation and other bits...)

Is it possible to use E-Commerce and OpenResort simultaneously...? What would have to do?

PS I understand that E-Commerce is use in OpenResort, but why not branch off of E-Commerce and make a special version to be bundled with OpenResort?