have done five floors with SL extensions, used to have the aluminium poles supplied by omni vac but they are extremely heavy for sustained work at that height unless you can work vertically all day as opposed to having to "tilt" the poles sometimes to get the right angle.... the clamps that are supplied with omni vac (unless they have changed them) are next to useless especially when raining, they are basically just jubilee clips.
Buy a triple motor vac (same as omni supply from dual pumps) get the poles from gardiners and then buy a stihl gutter kit to get a very light weight u bend at the top of the pole, save yourself cart loads of agro and a nice few quid.
cameras are available from
http://www.dogcamsport.co.uk/ ask for Ed. The best customer service I have received anywhere.
hope this helps
greg