Im not sure I understand what you mean about the base address.. you mean fixed pointers like the ones I posted for geiger's snes9x ?
Im sorry I don't. But It probably can be found easily by loading a ROM and then searching in the program's RAM for the first few ROM bytes.
Using cheat engine for example, Search for the first like 6 Bytes of the ROM, once you locate it, Search the RAM again for the memory address where it starts and you'll have the ROM pointer, which should be static.
Logically, Other important pointers like VRAM, RAM etc.. should be close-by.
Just remember to to flip the bytes order when searching for the pointer like I said.
If you find the ROM Bytes at address 0x10804020, you'll want to search for 0x20408010
Also, snes9x has many open-source ports, if the source code is available for this one, it might help to figure out the other pointers close to the ROM pointer