We are sailing on 01/21/07. I found a Lincoln Towncar for 65+gratuity (90.00). This is from Hobby to Galveston, a little more from Bush.
http://www.extremeelegance.com/GALVE...LIMOUSINE.html
Check them out they seem pretty nice. The rental car that I researched was from Galveston to Hobby for 44.00. The airports do not have the added one way drop fee.