Here is a list of RPO codes (regular production orders) basically the order list that you would check off what you wanted on your new car and wrote a heck to pay for it (you couldn't order a car without paying 20-60% up front with the amount down dependent upon how "saleable" your combination would be if you couldn't pay for the car upon delivery).
If you had the cash you could walk into any dealership singing the Burger King jingle "special orders don't upset us!" and get the car of your dreams. You of course paid full list price since the sales manager knew you really wanted it; so he wasn't going to offer a discount on anything, and he would low ball any trade in. This is why so few people actually ordered a car instead of buying off the lot.
You could almost get anything you wanted. Although some things were limited.
Talk about strange, I've seen a few. A friend of mine had a '61 4-Door Bel-Air with Power Windows. I've got a '63 here, Impala 4-Dr HT, 283 car, PG Trans, with a factory Radio Delete. And of course there are Impala SS's with 6-Cylinder Engines and 3-Speed Column Shifts.
Lots of weird combos exist. Sometimes they were purchased as a fleet vehicle were the business decided what was important and then went as cheap as possible on everything else. From everything I have seen a strange option combination on these cars don't make them worth a lot more. The things that make them valuable are the 409 engine and optioned out (every luxury option available) convertibles. Four speeds and SS packages are probably next on the list. One thing I have yet to see is an optioned out 409/425 HP convertible, probably because the owner didn't want the solid lifter cam maintenance that this package would have required.