When Retrostuff shared with us new information about the CD-i 450 and the CD-i 550, we found some remarkable trivia bits: The CD-i 550 was, as far as we knew, marketed under the Magnavox brand and released specifically in the USA. In USA, the Magnavox brand was used for CD-i because Magnavox was better well known compared to the Philips brand. In Europe, this is the other way around. Philips started to release CD-i players that had an integrated Digital Video Cartridge installed, marketed as the Magnavox CD-i 550 in USA and released as the Philips CD-i 452 in Europe. Now it seems that a Philips CD-i 550 player also exists. This also had an integrated Digital Video Cartridge but also, in contrast to the Philips CD-i 452, a Digital Video identification badge (the black marker on top of the cover, on the left side). I've only seen this marker in USA products, but this was clearly a European product!
Another remarkable thing is that the Philips CD-i 550 was the first CD-i player bundled with a gamepad instead of a thumbstick. The thumbstick was some kind of a trademark by CD-i: Philips pointed out this way CD-i was not purely focused towards games, but it was designed to give interactive television and cursor control to the user. Later on in the life of CD-i, Philips realized that games sold far better than anything else. It looks like the 550 model was pushed in Europe to focus on the gamepad inclusion more than the integrated Digital Video!
[Thanks, Adrian Zanoli]