what i can tell you is that my progress bar is back. I am not sure if any of the above actually helped in getting it back but there is definitely no harm in trying (I've tried all of the above mentioned techniques and neither did it hurt my system nor did it seem to actually have an impact on the problem. Deleting the Finder P-list seemed to make my Mac go a little faster though but that could have been an illusion ;-) The Progress Bar just popped back up one day right out of the blue, so it might have also been an update on something. I'd advise you to try and see and until then you can check how far along the progress is by just hitting the space bar when you are on the folder that you are copying your files to.
I was just having the same problem. I was transfering files from one hard drive to another and there was no status bar to tell me how long it would take. So I looked at this thread to find answers. Only I never had to do anything!
Come to find out the status bar was hiding on my second monitor. Anyone having this problem, check all around the edges of your monitor(s) and if your using more than one desktop,ie..Lion users, make sure you look there too. Chances are it could be stashed away.
Hey I must say this was about to drive me insane but yes I dont knw why I didnt think about it before, it happens all the time with other windows just didnt think the status bar would do it. THE SUCKER WAS ON THE 2ND MONITOR THE WHOLE TIME. IF YOU HAVE THIS ISSUE AND A SECOND MONITOR THATS THE 1ST PLACE I WOULD GO LOOK!!