I have got my plugin working with Rails 1.2, and its now sitting on the open.bluefountain.com repository. Here's a quick guide to install it:
1. Ensure you are using Rails 1.2, otherwise it could go horribly wrong 
2. In the root of your Rails application, type the following command:
script/plugin install http://svn.open.bluefountain.com/toffee
3. Edit app/controllers/application.rb adding so it looks as follows:
class ApplicationController < ActionController::Base
include Toffee
...
end
4. Add the following line to config/routes.rb, before the default route and any other routes you've added:
map.from_plugin :toffee
5. Then, add the following line to any models you want Toffee to manage:
class MyModel < ActiveRecord::Base
enable_toffee
...
end
6. Now, with your app running, go to URL '/admin/my_model'. You should be presented with a list screen for your model.
For more detailed options, and how to tailor the screens to your needs, check the README file.

I tried it and it sucks!