I read that people use their diamond dust coated file on their leatheman to sharpen their knife in the field. This is useful since you can leave the sharpening stone at home and use the space for something else. But does it do a good job compared to a sharpening stone?

Also, how do you sharpen your multi-tool blade if the file is atached to the multi-tool? <img src="/images/graemlins/confused.gif" alt="" />

I'm asking this question since I see that the leatheman Surge has a detacheable file, which solves one of the problem.

It does an ok job, it puts a good field edge on, but it isn't quite as good as a DMT stone. Most people here carry a fixed blade or folder along with the multitool so that knife is the one the does all the cutting, which is why they use the multitool to sharpen it. If you want to sharpen the multitool blade then you need a seperate stone, since up until the Surge none of the tools had removable files.

I heard a rumor that the 2005 leatherman's (Core and Surge) have a removable file. Anyone know of any truth to this rumor?

Yes it does, you can interchange the saw and file on the Surge <img src="/images/graemlins/smile.gif" alt="" />. Check out Doug's report on the SHOT show 2005