What is a very simple to hack up IDE to get automplete/intellisense for my own language and syntax highlighting? The output will be for .NET and maybe in C++
http://www.e-texteditor.com/ making new language bundles for e (and Textmate, which e is based on and the bundles are compatible with both) is fairly simple and extremely well documented.
I'm not clear about the "my own language" and "output will be .Net and maybe in C++". The own language part there are many editors like UltraEdit and the like. When you add .Net it make me think you want to use Visual Studio Shell to make your own IDE.
That said, some editors do give you "F5" build experience by calling into the command line build engine.
Hope this helps.