Hmmm... you mean on the still camera. Still a bit of a hassle but might work.

a test
 

Canon EOS lenses don't actually stop-down the aperture except during an exposure or when the depth-of-field preview button is pressed. So I set my RebelXT to manual exposure mode, set the lens to f32, and removed the lens while holding the depth-of-field preview button. The lens did stay stopped-down to f32.

This would be awfully cumbersome though. I'd prefer if the Brevis EOS lens adapter connected to the lens contacts and passed the connection out to some pins on the back. Then I could wire up one of my EOS camera bodies directly to those pins and control the lens. To keep it from being such a cumbersome combination, maybe I could strip down the EOS camera body to become just a couple of buttons, a display, and the control dial... That would probably be easier than reverse-engineering the EOS lens communication protocol and programming it into a microcontroller, and old EOS bodies are getting cheaper and cheaper.

Of course, if the lens communication protocol were reverse-engineered, it might be possible to control the lens motors and for follow-focus, although I'm not sure if they move in small enough steps to rack smoothly.