Many have maybe already started to play/completed the fantastic Crysis game with the stunning DX10 graphics which require a powerful system up to date. I have been playing this game myself for some days and what impress me most is the game engine that lays behind.
With the game Crysis you get a editor called "Sandbox" This looks like a very powerful editor and I have not yet figured out how to use it. It's the kind of game editor that is really breathtaking since you can import 3D models into the game and change the landscape and the gameplay completely if you know how to use this stuff.
The brains behind the Crysis game and the Crytek engine is the Germans which have made this stunning game engine which you can read more about here http://www.crytek.com/technology/cryengine-2/specifications/ (http://www.crytek.com/technology/cryengine-2/specifications/)
Why I made this post about another game engine is because I think that the Quest3D engine will be weak at the end if VSTEP is going to open up for more 3rd part add-ons or 3rd part content in the future. I have been reading that just to get add-ons into this game will require a huge amount of programming etc. Why then don't you take a look at the neighbors fantastic game engine and ask the question: "What if we did use this one..." It looks to me that with such powerful editor anyone can add their own stuff into the game if they just understand how to use the editor.
This engine does probably cost a lot but why use a lot of time on programming something new that already exist? It's like reinventing the wheel that someone else did invent. I see more and more suggestions at this forum where people wish themselves more advanced stuff for this game. I doubt that the Quest3D engine will help you much even if this game engine also is able to render great graphics.
But take a look at the Sandbox in Crysis if you got time. It's really a impressive editor and it was also a part of the demo of Crysis. Sandbox just shows how you give the player of a game the freedom to customize it on your own.
Think about it....