I jumped the gun and finally made the switch to a full frame DSLR, namely the Canon 5D Mark III. I currently use 3 lenses on it, the Canon 24-105mm f4 L IS, Canon 70-200 f2.8 L IS USM, Canon 50mm f1.4 USM.
Now one of the very first test shots I did with it (you can see the full version on flickr if you click on it):
This has been shot at previously unreachable ISO 2000 to get fast enough shutter speeds despite f2.8. After all we are talking about a moving train. The focus is snappy and spot on, no shutter lag and the quality is just amazing.
I’m quite curious as to what results I can produce with this in a couple of weeks, but it does certainly look promising.