Also might be worth checking out West Marine (if you are pretty handy.)
You could take one of their steering consoles(which is the trickier part to make ) and make up the pod seat yourself. A little marine- ply and fibreglass and you could attach a seat to the console.
Do a search in West marine for model #'s 3704020, 3704038, 386799, 419665.
They have consoles from $180.00.
http://www.westmarine.com/webapp/wcs...37648&y=5&x=27
Think it was boatster on ribnet who made his own jockey seat ,so do a search and may give you some ideas;
cheers Dal