Hi - I'd keep it simple so it works at any size in colour and black and white. You will run into problems with legibility if you try and put logos on balls - there is also the question of copyright of the other logos.
We quite like #34 however its got too much of an outline around the balls, could you also maybe do something with the spikes coming off the back of it and make them more streamline? Thanks.
Uploading tweaked version now. Don't want to reduce outlines too far or you will lose legability when reduced on letterheads, website etc. Let me know if there's anything else you'd like to see - colours, typefaces etc.