Check out Wav Corrector: http://www.wavecor.co.uk/. In order for CD burners to correctly burn a continous mix, the wav files need to be in specified increments. I forget the details but Wav Corrector will only allow you to split a long track in the requisite increments. I recently broke down my 70+ minute mix into over 60 tracks. The transitions b/t the tracks (wav files) are seamless (using the disc-at-once burning option).