3Dish

Not really. Basically, the thing about blender, Model Resource, and sketchup is they are essentially providing the "images" of the people. Think of it as a grid: these files will give you arrays with the different points in three-dimensional space, like (1,0,0). However, this has nothing to do with how you draw the object: for example, you have to take into account its relative position to the camera, the camera's rotation, if other objects are in front of it, and then take into account the distance between the object and the point (creating the "3-d" effect). All of these calculations and code must be taken into account by the programmer, and there are NO SHORTCUTS to these steps: there are no functions, there are no packages, there are no classes, that make this easier in Greenfoot. Its all up to you. Now, learning these things takes a long time: I have been learning 3d for a year and I do not believe I am quite up to the challenge of making a star fox game. However, I am still working on it and perhaps one day my obj file reader and my z-sorting will be simple enough and powerful enough for others to work with. This is not that day.

If you want to do 3d, either you can make your own in Greenfoot, like MatheMagician said, or you could use ready-to-go 3d engines. I know that Unity has a free version and Valve's Source Engine SDK is free (as long as you have a Source game. If you don't, Team Fortress 2 is free, thus, free Source SDK). I haven't used Unity (yet) and I've used Source (before I tried any programming. Stupid me). I've heard Unity is great (it's made everything to iOS and Android apps like Temple Run 2 to Ultra HD computer games like Slender: The Arrival) but you don't get everything with the free version. The full version is expensive (1,500 to several thousand if you buy additions to it for iOS/Flash/Android/etc.) Source is outdated, although many great games have been made with it the last couple years. Parts haven't been updated since 2004 (the year it was published) and the User Interface is not real user friendly, and glitchy. The above two are what I think would be good if you want to start making 3D games. There are several others, like Unreal SDK (free for non-commercial/educational uses), but I'm not sure which are free, and which are good, considering the only engines I've looked into at all are those above 3. Also, going into 3D design is a lot more work than making simple 2D games with something like Greenfoot (Greenfoot is also easier to use than other 2D engines). I'm going to work with Unity or Source only IF I think I can handle it, and have had more game design experience. However, it won't be devastating if I can't do it now, since they're free.

here is a Wikipedia link and here is a Nintendo wiki thing on it.

Hmm, interesting. But I can't seem to find any download or development kit for it. I see a bunch of people make their own engines, but I haven't found much, except one on yoyo games, but seemed a little complicated

Mode 7 is a technique for programming a background texture on the ground. Its pretty much just an efficient mathematical equation that some people have converted into code. It is not an engine or a base for you to build a game out of.