I see your point Trevor, they're not the most robust connectors in the world however they're cheap and readily available anywhere, so if you forget your cables at a display site just make a dash to your local Maplin/Currys etc.
For that reason however I am leaving considerable blank area (i.e. no copper) for those that wish to redrill and mount their favourite connectors. The 3.5mm connectors I'm using are the panel mount type, but mounted on the board its self and wired (2 per box, both in and out linked internally). It will probably make more sense with pictures when I get the V2 prototype boards in. I am holding off ordering boards until I get all parts including boxes to confirm dimensions - datasheets rarely 100% match real life dimensions!
1000x 4 way speaker connectors have arrived, and I shall be drawing up designspark footprints for them over the weekend after measuring a good handful of them.