This is interesting...if only because this question has been asked before, and the "official" response was that the "motherboard offsets" were different, making the conversion impossible.
If in fact transforming a D900T into a D900K IS possible, then never giving customers this upgrade option and instead "forcing" customers to upgrade to the mechanically inferior and, comparatively speaking, performance inferior 9890 is rather reprehensible on the part of Sager et. al.
For those of you who have successfully made this conversion, where did you obtain your components from? And, can I assume that these upgraded machines would be fully Vista capable with the concurrent upgrade of D900T problem hardware?