bit of a thread revival to update my progress.
After a lot of fiddling and substantial loss of blood, I have got my case looking a lot more how I expected it. Bought the extension lead for the 4/8pin mobo lead so it can be run around the edge of the board rather than over the top
Reconnected the SB X-Fi which has the front panel connector nearer the front of the case so the cable doesn't have to stretch so far.
Have replaced the rear 12cm fan with a Noctua to keep the noise down a bit and benefit from the nice meshed lead connecting it to the mobo connector nearby rather than the ugly red and black 3ft thing that comes with the original. The lead to the top 14cm fan has been tucked away out of sight.
Have moved the DVD drive down a bay to allow me to use the top bay for cable management. Have bent back a drive mounting to give me a hole big enough to get the cables through and down the side into the cable management area rather than by the side of the mobo. (cue blood-loss).
Have tucked the 24 pin mobo connector around the back of the mobo and under the notch in the sound and graphics cards. It is a tight squeeze and I hope won't cause any problems but the connector is in an unusual place on the Asus.
Main thing though is that I've turned the hard drives through 180 degrees so that the cables are pointing out of the front of the bottom fan area rather than out the back near the psu. A bit of cable tidying allows the cables to go through one of the holes at the side of the fan area and then back into the cable managament area. This cuts down the amount of cable on view significantly.
Have also replaced the Sapphire 4870 with a budget 260 which has a much neater enclosure as well as being a tad faster in a few games.
If anyone's bothered I can post pics. Quite tempted now to spray the interior black to match the board and other components. The gold coloured heatsinks on the p5q would stand out quite nicely I reckon (sad I know). Might even spray paint the thumbscrews gold to match
Have to say that the 300 is actually growing on me though it's not the easiest case to work with.