I'm sure it would be more for them to put in the 5-speed but in the long run it would be worth it. The complete kits usually go for aroung 3,200.00 or so. Spend the money once and be happy with it.
If you are mechanically inclined the swap isn't too hard to do in your own shop (or garage). I would imagine that it has even been done in the driveway a few times.
Another option is to do what I did and put in a t-5 out of a third gen. If your plan is to smoke the tires and do any speed shifting then this option will result in equipment failure, but if what you want is a fun highway cruiser you could get many years out of a t-5 and they can be found for $300-$500. Mine has been in for over 5 years with no problems, also behind a stock 350.
Whatever your choice, good luck.