grid++ is a kind of java + ajax + IDE ===> web application development framework
There is a lot of similar development framework in the market.
Netbean also provide a web application development framework and you can choice php + ajax or java + ajax.
Here is the link :
http://netbeans.org/kb/docs/php/ajax-quickstart.html
Grid++ has JAX technology which is what you describe, but Grid++ is actually native framework that can optionally run on the Internet/Grid++ which eliminates your distribution problem by simply adding your Live apps and games into a App-Store, and of course you can create native exe, and Grid Computing of course which allows you to harness and use idle computer power, but I don't want to get to much into detail.
Our Form Designer is completely written from scratch to make the design-time work properly on all platforms. The Form Designer is simply a modified TPanel, the design-time handles too. The trick is that we are actually have two forms during design-time, 1 the TPanel and 2 in the background a real TForm, and any change we do on the TPanel we sync to the TForm. If you look at the extensions of the form files, you will see f++ which is the object file for the TPanel and ui++ for the TForm.
Unfortunately I can't share code about this, but I can offer you my help and advice when you get stuck