After fighting with WDC's simulator for a while I got fed up and wrote a simple W65C816 emulator in C++ which compiles under Windows, Ubuntu and Ubuntu Mate on a Raspberry Pi and supports a much bigger address space.
I've also ported the core C++ part to a Diligent ChipKIT WiFire (a 200Mhz PIC32MZ board with 512K of RAM and 2M of Flash ROM) which can simulate a much bigger (and probably faster) system than a real W65C816SXB for a third of the cost.
The code is here
https://github.com/andrew-jacobs/emu816Its not perfect and there is no decimal mode or I/O yet but its useful for tracing ROM code in places that the SXBs don't let you get to easily. I shall continue adding features as I work on my 65C816 code.