Having had a good look through that list of parts, if you're conversant with how a RB works it should be relatively easy to do.
However I'd want an ADV, so any sugestions on what to get/where to source it from?
The AP one is out as it's the counterlung T as well, can you get a "Bob-o-matic" that fits in a P port? or in the exhale hose? or is there a better alternative?
Has anyone tried kit from these people
http://www.master.pl/~nemotech/rebreatherparts.htm ? (there is a quite nice looking ADV but it's priced at $230!!)
Regards
Simon A