Bought mine from BoardersMall.com. I don't see them on their site anymore though. You might give them a call. I will say that mine did not show up in the best of shape. Also they did not come with all the hardware. I contacted them but, never heard anything back. Had to go to the hardware store to get the bolts. They were under $100.
Target sells stainless wastepaper baskets for 19.95 that make perfect 8" speaker cans. All you gotta do is glue in an MDF ring to teh inside, and then figure out how to mount them. We drilled and bolted them through the tower, using thick rubber hose and washers as isolators to keep the vibrations from ratteling things loose. Two seasons and theyre still great. Heres a couple of crappy pictures. Please pardon the appearance as the boat is a work in progress...
I'm mostly impressed with the fact that they have the built in indentation for the subsequent
installation of halogen lamps in the front of the 'cans'.