I just tied off a hop bag with 1.5 oz of Cascade and threw it in my keg of IPA thats already 1/2 gone, within less than a week of kegging it
I didn't dry hop it, and after tasting the other half of the batch, which had 2.5oz on it, I just had to give my keg a little extra hop blast!!
If you really like it with the extra hops, why not just add it in the keg, in a hop bag? I remember on Brew Masters they ran the different beers through strainers filled with whatever ingredient they wanted to try. I'm sure the more time on the hops the better, though. Maybe some sort of tea bag?
Edit: How bout
these bad boys? Comes with 200 for $8.
Here are some larger ones. Only come with 50 though.