Sure you saw they were part of the November 12 G-Shock release, however not sure on US release. Do you have the GB-6900A in the US yet, looks to have reached the UK.
I haven't been keeping tabs with gshock like I used too. new hobbies got me distracted. I see the new bluetooth 6900 is on the main gshock site for the US but not the 5600 at all.
I agree, Rising Red series was more striking. These on the other hand seem to not have the 'Wow' factor. I think after the Rising Red series, it was going to be hard to better that. Still have some nice pieces in this collection. The blue could have been a bit more dominant in the colour way. I know they have the GB6900 but I would have preferred it if they had a DW6900 version.