Richard,
integration of the eCommerce Templating System (ETS) with the ACS Templating System (ATS) would require a rewrite of (part of) the ecommerce package. I agree with you that it is desirable to replace the ETS with the ATS. Yet, there are many other things in the eCommerce package that could/should be refactured. The product categories for one, or the user classes, or the eCommerce mailing list.
My preference would be to phase the current eCommerce package out in favor of several smaller modular packages held together by service contracts. A core of eCatalog, eCart, eCharge and eShip would replace 80% of today's eCommerce package. I think that replacing the eCommerce package would procude a better more flexible solution.
In addition, other packages could use some of the packages too. Like the events packages, which currently requires the entire eCommerce packages, just to accept payments for events that come at a cost. The events package doesn't need or uses the on-line catalog or allows customer reviews. A combination of eCart and eCharge would suffice.
Anyhow, the ETS uses the standard ADP for it's templates. A template gets parsed and is inserted into the ATS template as a chunk of HTML.
/Bart
