I also got one nice air-to-air pic over Poland during my flight FRA-VNO.
I was aboard Lufthansa B737-500 on flight LH3252 cruising at FL350 somewhere in the middle of Poland. And I noticed a Singapore B777-200 approaching from the north very fast. I tried quickly to turn on the camera and I managed to make one pic. I did not had time to zoom in so the picture is without zoom, basicaly its the view I had with naked eye, the B777 was really close. It's a pity it had no contrails.

click to zoom
I am guessing it was SQ351 flight CPH-SIN. The picture taken at 2007.11.24. Not sure about time, around 1200-1230. I dont have a clock, and my mobile was turned off in flight

Several minutes before I also saw B733 KD Avia above me passing very fast without contrails, but I was not fast enough to capture it.
