Kris Moore of PC-BSD/FreeBSD wrote to the Intel mailing list this morning (here's the message) asking about whether the UMS Intel legacy branch will be maintained. FreeBSD/PC-BSD lacks KMS and GEM support at present, but this UMS driver allows their Intel users to run a newer DDX driver without the said requirements. However, as is the case, this branched legacy driver will not receive anymore work and Intel's OSTC X developers really don't have much interest in non-Linux platforms.
The good news, however, is that the FreeBSD Foundation is willing to finance a developer to work on bringing kernel mode-setting and Graphics Execution Manager support over to the FreeBSD kernel.
Apart from that, there is already a usable solution in OpenBSD current (4.8?) and DragonFlyBSD is working on something similar.