Well, it has been talked about quite a bit, whether non-Sawgrass inks would work well or even at all in a Ricoh printer. There is currently a GX7000 with refill carts and ink being sold on a well known internet auction site. But, not being sold as a startup package, but a used and working system set up by the seller, including a mug press and mugs, and has photographed the mugs he's printed with it too (which don't look like he got the set up profiled which is a shame)
Obviously, with Ricoh not making a wide format inkjet printer, this discovery is not going to lead to a licensed system in the eyes of Sawgrass, even thought the inks in question were proper licensed ones, not cheap Chinese stuff. So a shame, but at least the question is answered.
- I have purposefully not linked to the auction in question, or mentioned the ink brand used, as this wasn't intended to be an advert for the auction of the inks, but more informative to say that in theory it is technically possible to not use Sawgrass inks in a Ricoh successfully.