For your specific questions, the answers are 'no' and 'not really'. Both derive from the fact that photokina's more of an industry exhibition than a consumer show.
When I was there two years ago, there were a number of cameras that were only on display, or only available to the press. Not many, but a few. There's certainly no shortage of cameras to try.
Also two years ago, Kodak was giving away samples of Ektar film (which was brand new), and like any conference there's promotional items being given away. I wasn't there looking to buy, but to my eyes it didn't appear there were any vendors set up to offer individual sales (large trade orders, on the other hand, are a big part of photokina). I suppose it would never hurt to ask, but there were definitely no "€100 off for Photokina guests!" signs.