Francisoft, that is a good idea, i have begun a similar project a little over a year ago, which wont be posted till it hits 0.9beta (its at 0.7). I built ground up using SDL in C++, its not 3d, but it handles tilesets, maps, and a gui, along with a half assed scripting language at the moment. Im not going to go into detail on the project, but am willing to provide you with a few pointers that would have/ did help me alot.

1. Make sure that you pre-plan everything, and in this case OOP is your friend. Think along the lines of interfaces, I would create differant classes, one for font, one for tilesets, one for maps, exc, each that are self, or near self sufficient. Make sure you pre-plan what interfaces each class will use, and how it will operate BEFORE HAND. This should be in your design document.

2. Use polymorphism, it is going to help make your engine more customizable. How I did this was create abstract Tileset classes, with the same map class you can make isometric or overview games, amazing. You can also use this to take advantage of certain hardware abilities *hint hint*

3. Cross platform. Its a good idea to do that in this case, you have verge, sphere, and scrolling game development kit to compeate with, your going to want this for an edge. Keep with the compile-once run anywhere approch. That brings me to my next hint

4. PRE-PLAN your scripting engine to include upgrades. Also, it would not be a bad idea to make the scripts compilable. The way I do this is compile to a byte code. Easy enough isnt it.

If you need any help/source, i will be happy to provide you with a little help on this project. While my project IS commercial, I am always interested in helping the adventurous out.

FrancoisSoft, you are the BIGGEST NEWBIE on gamedev, you should be ashamed of what you said in that other thread...