Their is a strange clunking coming from my front end, it has been doing this since late last year and I can't seem to find the bad part?

So far I have done:
new shocks
new tie rods and center link
idler arm rebuilt
guide rod mounts
The clunk is strange it doesn't do it all of the time although the cold makes it occure more often. It usually does it as I am coming to the end of a stop say under 5mph, also if I am going down a steep driveway or apron it does it worse. Also it will clunk when I am going in reverse. I can feel the clunk in the brake peddal, it feels almost like the ABS is kicking on?

Usually it will go clunk, clunk and I feel it in the peddal.
Now I have checked everything, it is all tight. The shop that did my alighnment commented on how tight the front end seems to be.
Any ideas? I suspect the upper control arms but I don't want to replace them at this time if I don't have to. ie no throwing $250 worth of parts at it hoping they fix something. I will do a complete front end rebuild later this year but I would like to fix this clunk before then.