The difference between an emulator and a simulator is that an emulator emulates s60 phone via x86 instruction set and a simulator emulates s60 device with ARM instructions.
We are currently exploring the option to replace emulation debugging with simulation debugging.
There are many benefits to the developers to switch, mostly arising from the shortcomings of current emulator. The problem is that this technology is rather expensive. I believe that if the performance and usability of simulation debugging will exceed that of a current emulator then we can safely add it to our Developer and/or Professional addition of Carbide C++. Personally, I think that it should be there in Express addition to begin with, but am afraid that product planners and cost watchers will not be happy about my enthusiasm... In any case I hope that we will be able to add this technology to the toolset soon. Maybe initially as an addition to emulation and later as a full replacement.