Don't forget the 4matic models!! Here in germany, you can purchase the following S-Class versions:

S 320 CDI (SWB, LWB, 4matic)
S 420 CDI (SWB, LWB)

S 350 (SWB, LWB, 4matic)
S 450 (SWB, LWB, 4matic)
S 500 (SWB, LWB, 4matic)

S 600 (LWB)

S 63 AMG (SWB, LWB)
S 65 AMG (LWB)

So, you really have the agony of choice!

LWB when it comes to the higher class S models like the S600 S65 and S63.
SWB might fit an S450, and those below. Thats about it. I really never cared for the SWB look of the S. The car has too much body-mass and flow.

IMO, the S-class has been designed to be LWB. SWB just looks weird.

SWB looks alright too me.

The LWB ought to look better, it's more expensive.

aha, I should say MBUSA also sells the 1/18 Die-cast W221 S550 SWB crafted by AutoART for fun-collection, which is sadly made not in a good quality but a high price as the fine 1/18 C216 CL-coupe. What will the AutoART W221-AMG look like? Still on current module and standard to craft an S65? I cannot accept that!

S63 LWB ONLY

I can see the merits of a SWB S-Class for markets where a little smaller may be necessary due to fuel costs, street size, etc. A smaller "S" diesel or economy 6 cyl certainly make sense for those who "need" them. The S63 however is not a "need" car and should only be available as the "big dog" that it is, a long wheelbase, high powered highway cruiser. If you want "smaller", get the E63. (Audi should take a lesson here and stretch the S8 to A8L proportions and finally have a competitor for the S63)