You'd still notice the difference between a 300mm f/2.8 and a 500mm f/2.8 though - through your arm as well as through the wallet. Much as I prefer full frame, a smaller sensor (within limits) certainly makes sense at longer focal lengths - and the small loss of image quality may not be important if you're working in good light. I still think it's possible to build a good quality full frame DSLR that's no larger or heavier than the Olympus OM-1. And yes, I'm well aware that it wouldn't suit everyone - but I reckon there are a lot of potential customers out there who would like one if it became available. Unfortunately, it looks like the manufacturers are united in their determination to deny us the choice.