I am sorry I don't have any suggestions at the moment but I have just been thinking along the same lines. I did see a Sony model on Amazon that seemed to be getting good reviews but I really need to do some more research because my knowledge of blu-ray is just about zero.
http://www.amazon.co.uk/Sony-BDX-S500U-Blu-ray-Writer-External/dp/B0042X8PA8/ref=sr_1_6I am torn between the convenience of blu-ray and wondering about the wisdom of placing so much data on one disc.