Lots of people use Niner or Carver forks for converting to rigid.
I've seen the Carver Trail 490 on more than one conversion. [MENTION=197614]fietsbob[/MENTION] makes a good point about suspension correction and the Trail 490 is corrected, specifically designed for conversions.
Gravelcyclist.com has several examples of conversions along the lines of...
-Tim-