iv run out of ideas! (something rattling.. kind of)

apple

so i am out of ideas of where to search
I have a what sounds like a socket rolling somewhere behind the driver seat.
iv pulled apart the trunk and pulled off the package shelf to see if i could find something but i have had no luck.
The sound is only heard when i hit the brakes. i cant hear it roll back cause of my exhaust. It sounds like whatever is rolling is going for around 4 or 5 inches (its a rather long sound)

Maybe your Cat has broken loose.

the sound is in the car the cat is bolted down tight :]

Sounds like something in one of the tunnels that are on either side of the fuel tank. Access them by removing the panel in the front of the trunk.

When we took apart our project car we found a half a pound of beach sand and a really old and nasty bottle of schnapps below the rear parcel shelf, in the dead space around the gas tank.  You say you pulled things apart but were you this deep into looking?  You need to remove metal shields to see the dead space.

iv been in there but i will pull it apart again. more specifically it sounds like its from behind the seat belt reel or next to it. i dont have the rear trim installed. its my day off today and ill pull it apart and report back

Take the belt retractor out. There is a large space there for something to roll around in. I just had to use a magnet to retreve a washer  from there during a roll bar install. Remove the trim and then it's two bolts to get it out. You can see t he large openings in Cheryl's picture.

i have no trim and to get my seat belt out is a pita (rollbar) but i can see behind the seat belt reel from the trunk and there is nothing. iv pulled apart the package shelf and nothing. back to work i go!

Ok.... I fully suspect a nut or something similar behind the seatbelt reel.  I'd drive somewhere and stop abruptly, forcing it to be at the front.
Another option would be to use a set of ramps and see if driving the back of the car onto the ramps will cause it to come forward.
Then I'd pull the quarter trim in front of the seat belt reel.  Look in, around, and behind the reel to see if you can see anything that might be loose.
I'd try to remove anything you see with a 'grabber' or magnetic tool.  If you can't get it out, you can try just putting a magnet down in the space to 'grab' it.  If you can't get it out and a magnet won't hold it in place, then use some expanding foam sealant and spray it as deep as you can behind the seatbelt reel.  If you can't remove it - hold it in place.
Be careful though - if you left the reels out of the plastic bag the sealant can press against the reel and make the seatbelts harder to use.

is there any space under the rain duct behind the seat?

Not under the 'catch' that routes the water from the rain rail.  Below that is the seat belt town and seat belt reels.

i gave up for the day. and put it all back together kind of.
maybe something fell into the car near the door jamb is what im thinking thats why i cant see it.

so today.... 6 months later....... i finally found the sound!! it was just as i suspected it was under the rain rail catch where i found me a nice 10 mm bolt. now i have another 150 sounds to catch!

Thanks for the follow-up. I had a VW back in the '70s that had a thump when I depressed the clutch pedal, found a pair of vicegrips clamped on the cable.

Yeah, thanks for the follow up and thanks for resurrecting the original post to answer with. Kind of completes the loop!