Hi Mark,
For clarification,
ecommerce-g2 (abbreviated ec-g2) is a suite of packages that are not yet in alpha stage. Work continues at http://dekka.com/p2/xowiki/
ecommerce-2 will be a combination of the ecommerce-g2 packages that will "upgrade" an existing ecommerce package to use ec-g2 (and therefore is just a spec at this point).
ecommerce is the existing package which has a few serious limitations on OpenACS above 5.1, such as bug 2324. See bugs: https://openacs.org/bugtracker/openacs/?f%5fcomponent=56215&project%5fid=56106
cheers,
Torben
