I bought a used Island Air 2000 from a fellow Signs101'er for our Seiko. It worked ok, then I replaced the charcoal pellets and it now works fantastic! I paid $2700 between the used unit and the replacement charcoal. I know that's still a good bit of money, but I would do it again. Look on ebay, craigslist and the forums, there's good used units out there.
Gixxer, I tried a similar system to what your describing a few years back on an HP8000. You need a lot more charcoal to remove fumes than simple odors. I had an 800 cfm fan pushing air through 20lbs of charcoal and it did work, just not that well. The Island Air unit has 35lbs of charcoal on each side of the machine. Trust me, there's no comparison.