I did the same thing with my A/C. Do you have UDP? If so the proper size belt to bypass the AC pump is a Dayco 5060390. I believe that makes it 39 inches. You will have to come up with someting to go in place of the pump as the alternator attaches thru it. I cut two lengths of steel pipe to the same size as the top of the pump to compensate for it. Once you take the pump off you will better understand what I mean. To remove all the a/c lines, a Sawzall comes in very handy. Just be careful you dont accidently cut something other than the lines! And dont forget to pull the condensor from in front of the radiator.
Also, there is a very informative article about lightweight batteries at SHOTimes.com. It is under the product review section. You may want to avoid changing you battery out if you have a big stereo though.
Aftermarket seats are another great weight savings. The stock SHO seats are very comfortable but very heavy. Cobra (subesports.com)makes some pretty nice stuff and you can get a mount from them specifically designed for the Taurus.
The downside of removing power windows in favor of adding rollups is that you need to change door panels. I wouldn't be suprised if they are discontinued from Ford, and chances are you wont find nice ones in the proper color at wrecking yards. Also you will only save about 1 3/4 lbs per door. (I did this in my car and weighed the assemblies).
I would recommend taking a look under your hood. Do you really need/want all the pretty plastic covers? ie shock towers, radiator, ignition system, hood pad, etc. They dont weigh much individually but it all adds up!
Hope this is helpful!
