I very much extremely doubt that will be the case. Right from the beginning, James has been saying the X5 will be tuned to be more 'neutral', as it is intended to be a more serious audiophile-oriented DAP.
I'm guessing reihead's use of the term 'warm', within the context of his first impressions, more probably relates to the X5 perhaps having quite a 'full-bodied' sound.
I'm like you, though, jj69, I'm hoping the X5 won't have a noticeably coloured sound.
I am hoping for neutral too...could have been the iems he used. One Japanese review (read via Google Translate, so take it with a pinch of salt) seemed to suggest that the unit allowed headphones and isms to show their own coloration without imposing any of its own...
Guess we need more reviews
You are right, sounds more neutral, a complete easy to listen sound