For a MTB project, seems like an unraked, untapered segmented crown fork would look more at home than a road-style fork. Good thread on construction of these over at; http://forums.mtbr.com/frame-buildin...es-711257.html
An MTB tire is going to provide much more suspension compliance than a skinny, flexy road style fork ever could hope to achieve, much better to have a stout fork for offroad+disks that will not bend/break.