This has been a bit of a moving target, but this is the current status as of 2020-12-15. GDRV offers an 8K suspension upgrade on the build form. This is NOT the Independent suspension, but rather a standard set of axles and leaf springs rated at 8K versus the standard 7K.
The MORryde Independent Suspension can be installed prior to delivery from the factory to the dealer. However, it is no longer done as an option directly through Grand Design (where GDRV pays MORryde and invoices the dealer on the build) due to liability issues. Thus, you will not see it on the build and price tool.
Instead, GDRV will transport the RV to MORryde post-build (for a nominal fee) prior to going to transport (to the dealer). Long story short: It is possible, but MORryde needs to be paid directly by the customer. This should be coordinated by the customer with the dealer, GDRV, and MORryde.