Mike-
I guess you could say dry sump is an option in the form of a GT3, GT2 or Turbo since they have a dry sump engine.
I guess one could technically add a dry sump pump to a normal 996, I have even seen it done on a pushrod 356. It would take a lot of "hot rodding" to do it though and the end result would not be as effective, since the entire crankcase really has to be redesigned to do it right. There would be no advantage to doing this unless for racing reasons in a class where you had to run the 996 crankcase.
Here's a little history on the latest GT/Turbo engines in the GT2 GT3 and Turbo cars.
Their engine really is a modified air cooled 911 engine that started life in 1963 in the first 911 cars. The air-cooled 911 engine is a modular design with a separate crankcase which accepts individual cylinders topped by individual cylinder heads. This modular design allows easy design changes and changes in displacement.
This very flexible 911 engine was modified into many variants for racing use, the 904/6,906,910,911RSR are a few using this engine.
In the mid 70's, water-cooled 4-valve cylinder heads were added to the 911 engine in the 935 creating a hybrid water-cooled head/air-cooled cylinder engine. Variants of this engine were used in the racing 936 and 962 as well as the 959 street engine.
Finally in the late 90's the engine was modified for the Le Mans GT1 cars when water jackets were added over the cylinders to create a fully water cooled engine. This basic engine is the same one that is in the current GT2/3/Turbo.
Through all this change the basic dry sump crankcase design that started in 1963 was retained and if you look under the first GT3 cars imported to this country you will see the same basic casting as under any air-cooled car. About half way along in production of the Mk2 GT3 the crankcase was changed to eliminate any external casting elements of the air-cooled crankcase. No internal changes of note were made.
So if you want to see Porsche history at it's best look at one of these engines. Technically, since the bolt pattern is the same, one of these engines could be bolted up to a 356 transmission!!! It is a very complex engine to manufacture with separate water jackets and cylinders. I am suprised Porsche has not re-designed it to simplify construction but save the basic design elements.
The normal 996 engine on the other hand, is a non-modular design with cylinders and crankcase cast together as one lump. The cylinders use a similar technology to that intoduced on the Chevy Vega and also the 928 and 944. As mentioned to save money the dry sump was eliminated.
This lack of history and blatant change in philosophy to make this lower cost alternative engine (and transmission, another story) in the 996 is what turns some people off. Particularly when Porsche makes the most money per unit of any manufacturer and it wouldn't have cost that much more to do it right. It makes me sick when Porsche management get up and make a speech, as I understand was done at a PCA Parade recently, to enthusiasts about how much money they are making.......keep the faith, your humble gearhead, Bob G.