http://boston.craigslist.org/sob/boa/4305317695.html
Saw this on craigslist . . . Might work for you if it's in good shape.
I ran a 55gallon and a 25 gallon tank on my boat. I yanked the 25 this past year, b/c I never used it.
I have a 2nd 55 that I've been planning on adding in . . . but haven't gotten around to it.