Within the last 10 years, what Sega games (if any) have they let other publishers release? Have they ever let another company localize one of their titles?
Acclaim had the exclusive North American rights to the Ferrari license for games. Their relationship with Sega was always good, so Sega eagerly allowed them a cut in order to get the PS2 port of F355 Challenge published. I want to say that Astonisha Story on the PSP was a Sega title that was published by Ubisoft, but I might have that situation completely backwards.
Acclaim also published the Crazy Taxi and Virtua Tennis 2 ports for PS2 and GC. There was also a ton of PC ports (Sega GT, Typing of the Dead, House of the Dead 2, Sonic 3D, Sega Rally, etc.) published by Empire in their Explosiv line.
Shenmue II (Microsoft) Rez (Sony) Space Channel 5 Part 2 (Sony) Sakura Wars: So Long, My Love (NISA/Tecmo Koei)
I think some of their GBA work was joint published by THQ. Astonisha Story was by a korean developer which sega picked up the rights to localize/publish it in japan and Ubi got the USA rights. Same with the sequal "Garnet Chronicle"/"Crimson Gem Saga" that was picked up by Sega for japan but Atlus for usa.
I can't believe I forgot that, Pinball of the Dead and Crazy Taxi GBA were both THQ issues. Is Sakura Wars owned outright by Sega, or is it a complicated relationship with Red? The PS2/Wii release of So Long My Love doesn't seem to have any Sega branding on it. Neither does the Qubed release of Rez on the 360, which I'm told is owned outright by Q! Entertainment and doesn't owe any royalties or acknowledgement to Sega at all.
Isn't Sakura Wars shared between Sega and Red? Anyway I think the downloadable Columns for Super Famicom (wasn't released on normal cart) might count here.
I think the GC port and maybe the PS2 port of 18 Wheeler: American Pro Trucker were published by Acclaim. And I think Super Monkey Ball for GBA was published by THQ; although I believe that game was also developed by an outside company. I can't remember as I don't have my copy on hand.
Sonic Rush (Nintendo DS) was published and localized for Korea by NINTENDO! Otherwise here's my exhaustive list of Sega's titles for the NA region published by other companies. THQ - GB Advance Altered Beast: Guardian of the Realms Crazy Taxi: Catch a Ride Jet Grind Radio Pinball of the Dead Puyo Pop The Revenge of the Shinobi Sega Arcade Gallery Sega Smash Pack Sonic Advance Sonic Advance 2 Sonic Advance 3 Space Channel 5: Ulala's Cosmic Attack Super Monkey Ball Jr. Virtua Tennis ACCLAME - PlayStation 2 and GameCube 18 Wheeler: American Pro Trucker Crazy Taxi Agetec - PS2 Space Channel 5 - Limited Edition That's about it. Sega publishes their own stuff in the US nowadays. All their Xbox titles are self published, as are most of their PS2 titles such as Virtua Fighter 4 and Yakuza.
Well apparently Haro no Puyo Puyo was published by Bandai. No surprise as it used the Gundam license. Mario & Sonic at the Olympic Games series is Sega developed, and published for the west. Yet Nintendo publishes them in Asia.
In the 80's many sega arcade games were published by the likes of Midway in the US. Same goes for Taito and Namco. Yakumo