Is the vibration in the front or the back? I had vibration from wheel bearing as well as tires, bad outer and inner tie rods. Though the sound in the back is likely your strut that is how mine sounded before replacing them all and if you have not replaced them ever then they are definitely wore out. Though not sure they would cause the issue you have been referring to but my front struts did make a knocking sound that was the metal part of the top of the strut moving up and down and hitting the sheet metal of the car where it was bolted in or the hood and it was hard to find where this was happening.
It wasn't until I replaced the front struts after a week doing the back that this sound went away. Also you will get a better ride quality of course changing those. If you do decide Rock Auto does have some quick struts which I have researched to be relabeled Monroe QuickStruts but not the economy ones and at about 90 a piece are a great deal if you can afford them.
I would try as Scotty said in regards to the tires and swapping them around to make sure that is not the issue. If you cannot find it just take it to a shop and have them diagnose it. While may cost you 60 - 80 bucks at least you won't just be replacing parts that are still good. But sure your close to finding it since alot has been changed.
Though looking back if you have not done the tie rods at least check this on the side. I had the passenger side of mine fail 3 times now and once was a moog part. take the castle nut off and check if it is worn out it should be pretty apparent if it is. AS well see if the inner can hold up the weight of the outer. It should be able to at least hold is own weight but if it is moving around like crazy that inner is worn.