Grant, that's a cool set up. I'm thinking it has something like a powered screw jack inside the box that pushes against the master cylinder to apply pressure. It'd be pretty easy to install that type of system too, just a single wire from the brake controller.
I decided to stay old school and plumbed mine vacuum over hydraulic. My Dad gave me a really cool brake valve that mounts to the steering column. It's from the era of our trucks so looks wise it fits right in. However I do need to add a hydrovac to the trailer. Right now I've just got the vacuum boosted master cylinder and it doesn't give quite enough pressure to the brakes.
I'll try and post a few pictures of some recent loads I've hauled with it and one of the brake valve next time I get a chance.
Thanks for all the compliments guys... I really appreciate the feed back.
Paul.