I put together this estimate for a friend of mine at University of Texas (DrJamesWood) and thought I would share the info here too. All costs are from B and H and are retail. You can get lenses and such much cheaper (new) on Ebay:
Fuji S2pro: $2,400
Nikkor 18-35AF-ED $499
Ikelite S2pro housing: $1,149
Ike Extended Dome Port: $149
Total: $4,197
Add Fixed Wide:
Sigma 14mm f2.8 lens: $799
Ike Extended dome: $Already Included
Total: $799
Add Macro:
Nikkor 60mm Micro: $389
Ike Flat Port: $149
Total $538
Add a strobe:
DS125 w/ sync cord and arm - $696
Smart Charger - $110
HTH
James