Mark, no. The idea is that acs-tcl should, ideally, be just Tcl code, entirely independent of the OpenACS data model. Therefore it must not "build on" acs-kernel at all. A nice bonus of that organization is that (with some extra hooks), you should be able to use all of the acs-tcl code outside of OpenACS entirely. All other OpenACS packages, on the other hand, are of course perfectly free to use all the functionality in acs-tcl - that's the primary reason for acs-tcl's existence, after all.