Thought I would break this issue out from my earlier post.  I did a search and found one other user that described this some time back but there was never any follow up information.
The machine is about 3 weeks old  and the creaking started after 2 or 3 days of purchase.  I now have over 100 miles on it.
I have lifted it a couple times, taken the wheels off, inspected anything and everything for looseness and found nothing. I initially thought that it didn't do it with the engine off but I have been able to disprove that by killing the motor and drifting down a hill in N.  To me, sounds like its coming from just under the dash. sounds like something loose and flexing/moving constantly when machine is in motion. I did find a hole  with a bolt thread  and no bolt on the panel below the dash but watching it ..it doesn't seem to move, might be for some accessory. 

[2015 Z Force 800 53/Trail EPS]

Many times squeaking or creaking comes from dry shock "I" bushings/bearings and as CFM uses almost no grease on anything this is one of the first things that starts making noise. Mine started in under a 100 miles..I have a video in the How Tos on greasing them.

Great video. I just got finished. Neither bearing could be turned by hand or with pliers.  Weird thing though. the sleeve at the bottom of the shock was non-removable. I could tell the bushing material was fused to the sleeve. Closer inspection showed that it was one piece not 2 like the top one. I worked at it for quite a while but that thing wasn't coming out of there.
Unfortunately that was not the problem.  It really sounds like its coming from just bellow the dash but there's nothing there I can see that would move except where the cab bolts to the frame and most of those bolts would be difficult to get to. 

I had a creaking on mine chased it for mths sounded like the front end
Found it the be the brace atop the roll cage on the front that the roof bolts too across the front
it was rubbing on the cage slightly
I put a slice of rubber under mine went way

May be worth a look

That was it ! I could have sworn it was under the dash. wasn't obvious until I took off the roof.  I guess its from the flex in that brace since its pretty thin.. but its strange seems like all would do it or none would.  Unless whoever puts the roll cage on at the dealer was supposed to put some dampening material between it and didn't.

I realized after I wrote above that unless there is supposed to be a washer or something in-between,  the root cause is over-tightening the bolts on the cross brace. Back them out a turn or so and the sound disappears. Sounds counter-intuitive I know but it works. 

Took a lot of searching for that noise lol
I recommend a pc of rubber if you ride rough an twisty terrain like I do but atleast you know where an what the issue is if it comes back

[2015 Z Force 800 53/Trail EPS]

When I was doing the cage mod, taking off the roof a, piece of old foam fell out..made me remember my roof up front would oscillate at speed and bang against a bar on the cage. Stuffed some memory foam between it to stop it 7 years ago and forgot about it.