When I saw your message I had to chime in. A couple years ago we put in a large shower and used a Swanstone shower pan...we very much regret this choice! It looks and feels very cheap, it stains easily and never gets completely clean no matter what we try. We are now going to replace the Swanstone pan after only 2 1/2 years and replace it with natural stone or tile. It really is disappointing!!
FYI, two of my bathroom have Swanstone shower pans that are 34″ wide — as much as we could squeeze in. Honestly, I am not sure which way I would have gone if I had known of the terrazzo options. In other bathroom, I simply don’t believe there was room for 36″. The other – it would have been tight and meant a narrower enclosure for the toilet. This particular decision would have caused me anguish: More room in the main part of the usually already small postwar bathroom, or more room in the shower? Such is the retro renovator’s life, alas.
And frankly HD doesn't know what they're talking about either. You do NOT have to use a Swanstone pan with Corian walls. In fact, you can find Corian showerpans to use with your Corian walls, just as you can buy Swanstone panels to use with Swanstone showerpans.
If you can use a standard size, definitely look into swanstone shower pans. Make sure you are looking at the pans that are made out of the actual swanstone solid surface material though and not the pans made by swanstone corp called "veritek." These have gotten universally lousy reviews on this board (pretty much anything made of that material). They have a surprising number of standard sizes and are definitely reasonably priced compared to custom.