I forgot to post that the DREW paper has finally been published in RUSQ:
Nicholson, S. & Lankes, R. D. (2007) “The Digital Reference Electronic Warehouse Project: Creating the Infrastructure for Digital Reference Research through a Multidisciplinary Knowledge Base.” Reference & User Services Quarterly 46(3). pp. 45-59.
The paper provides an outline for a digital reference knowledge base and some excellent data and theories on how to build one. However, the DREW project itself has never really materialized. I would hope that folks (Paula) could take this data and put up a repository and research service.