Dear Boyd (et al.),
At Indiana University Bloomington, we've been using LTI Basic (i.e., LTI 1.0) to authenticate from Sakai to WeBWorK since last September, i.e., the 2011-12 academic year. On the WeBWorK side, the primary new software is a Perl module WeBWorK::Authen::LTIBasic.
We have a test site that other institutions can use to test the LTI interfaces in their local Course Management Systems (e.g., Sakai, Blackboard, Moodle, Canvas, etc.).
For details, please go to the Administrators page in MAA WeBWorK Wiki and look under the Authentication section for the LTI Basic page.