Pretty much any camera will work suspended from a kite line provided winds are fair and there is some method of tripping the shutter remotely. I had a bit of spiteful fun with a local photographic society a while back, I asked folks to raise their hand for Canon or Nikon: result: it was a neat 50/50 split.I have a foot in both camps...and Leica too!
Modern cameras are getting better and better in terms of sensor sensitivity and this is a very good thing for KAP, where the camera is on the move and a high ISO setting can keep shutter speeds up.

So far the best of the 'full frame' digital cameras are beyond me in terms of weight and cost. The lightest in the class is the Sony Rx1 which at £2,500 is almost 'affordable'. At the moment all the action is in the growing family of APSC format cameras of which the, now obsolete, Leica X1 is still far and away the lightest of the bunch. At 280g it is beautifully light and the weight saving means I use it as my RC video down link camera. ..which brings the weight up to 800g when I use a big enough battery to power it for 2.5 hours.

Whatever camera you choose to fly I hope you will find photographs from the sky every bit as compelling as I do!