Sorry...I was away from my computer for a little while.
HYUNDAI, not Honda, is working with DaimlerChrysler. So far, the only definitive connection between them is the Global Engine Alliance (DaimlerChrysler, Mitsubishi, and Hyundai are working together to design and build engines) and a medium/heavy truck venture.
It doesn't seem like Honda is poised to merge with anyone. Although I think Honda/BMW would make a good fit, that's just my thought. Since GM owns 20% of Fuji Heavy Industries, a merger between Honda and Subaru (Fuji Heavy) doesn't look likely.
Chrysler Corporation owned a sizable share (about 1/3) of Mitsubishi from the early 1970s until the mid 1990s. Chrysler sold most of their holdings at that time. In 1998, Daimler-Benz and Chrysler "merged" and shortly afterward, DaimlerChrysler purchased a portion of Mitsubishi. They are currently working at developing vehicles together. The next generation Lancer will share much of its platform with a number of Chrysler Group vehicles including (but not limited to) the Neon, Stratus sedan, Sebring sedan, and Sebring convertible replacements. DaimlerChrysler's relationship with Mitsubishi has nothing to do with Mitsubishi not building the 3000GT.
GM owns 20% of Subaru and 100% of Saab. Since Saab needed more product, they are using Subaru and GM products. The 9-2 will be based on the Impreza wagon and there will be an SUV based on the Trailblazer. the 9-2 hatchback will be the standard Impreza wagon while the 9-2 Aero will be the WRX wagon.
And General Motors did NOT merge with Toyota. It never happened.
GM and Toyota formed a joint-venture in the early 1980s. The joint-venture is called New United Motor Manufacturing Inc (NUMMI) and it's based in Fremont, California. NUMMI began by making the Chevrolet Nova (based on the Toyota Sprinter), Toyota Corolla, and Toyota pickup. The Nova was replaced by the Geo/Chevrolet Prizm, which was recently replaced by the Pontiac Vibe. Toyota developed most of the Nova, Prizm, and Vibe to be sold by GM. This joint-venture does not mean there's any cross ownership of stock. GM owns no significant amount of Toyota, and vice-versa. Toyota is substantially more valuable than GM at the moment.
Once again, Toyota developed the Matrix and the Vibe, and GM wells the Vibe. Oddly enough, Toyota also sells the Vibe in Japan as the Toyota Voltz. GM and Toyota NEVER merged.