My father has this...
Has anyone else heard of this condition and/or recent research?

Not much but here is the WebMD Search:

WebMD.com Search For "Fever"

and

WebMD.com Search For "Unknown Origin + Fever"

I hope those help a little.

In my expert medical opinion your father has a fever. we're not really sure where he got it, but we know he got it from somewhere

Sorry, do you have any more info other tahn the fact he has a fever?

The fever could be his body fighting off an infection or be a sign of a virus.

Any other symptoms besides the fever.

Also if the fever is unusually high and doesn't respond to medicine etc to lower it, it'd be worthwhile heading off to the doctors for a checkup.