I received email from Deb Woods of Ingres this morning telling me that the Ingres C/Ruby driver and the Rails ActiveRecord adapter I wrote have both been made available.
Here's some more information in a blog posting and here's the actual page.
Hopefully they've made some improvements to my code in the last year or so. This was my first 'real' Ruby and Rails project, so I suspect the code has improved a bit since I sent it to Ingres. :) If memory serves, the code should all be under the GPL (but don't hold me to that... it's been a while.)