Geuf: As I said, I was thinking of mod'ing my Dutch bag with a zip, do you have any recommendations as to the best way to do it? Was thinking of unpicking the stiching along the long opening, between the "goretex" and the webbing strip that has the poppers for attaching your sleeping bag to and then sewing the zip in between these two layers. Is this the best way? I have a sewing machine so I reckon it'd be ok.
Greg: one thing I like about the Dutch one, can't speak for any others, is that it has large fabric loops on the underside to slide your roll mat in so you don't slide off it in the night. I also reckon you'd have to take a larger than XXL chest size before you found it restrictive, I'm only L myself and there is tons of room at the shoulders.