Hi all,
I've just uploaded to RubyForge a what seems to be usable version of Instiki-AR (that's Instiki with an ActiveRecord backend).
Unlike Instiki 0.10, this one is a normal Rails application, which means you can host it on Apache, no more ProxyPass and Madeleine madness.
Download link: http://rubyforge.org/frs/download.php/6251/instiki-ar-beta1.zip
As a beta version, it comes with some bugs and no documentation. If you need a manual to install a Rails app, this release is not for you anyway 
However, here is how to create a database and import data from Instiki 0.10 into it:
1. Copy config/database.default.yml to config/database.yml and edit it
2. If your database is MySQL, create an empty instance, and a user with grants to that instance
3. Run 'ruby script/create_db'. This script creates database objects in all three schemas (test, development, production). Note that it fails if an instance is not empty.
4. Run 'ruby script/import_storage -h' for command line options this script understands. Here is how I run it:
ruby script\import_storage -i c:\instiki -t c:\instiki\storage\2500 -o i.sql -d mysql
5. Open a console to your production (or development) database and execute i.sql in it.
Databases that I tried it on are SQLite and MySQL.
I am very much interested in bug reports and patches. The areas that are expected to be bug-prone are page caching, admin interface, All Pages, Apache/FCGI deployment and performance (although you need to have more than a thousand revisions in your wiki before it starts to hurt in some places).
Kudos are due to Rick Olson aka technoweenie for doing most of the initial porting effort.
Best regards,
Alexey Verkhovsky