In the future I also hope the sram will be mapped based on the softlist, instead of the current inaccurate header based mapping.
sram emulation is already based on softlist, in the sense that only the amount specified in the softlist gets allocated. nothing SRAM-related gets read from the header anymore, if you load by softlist
the only thing we still don't support yet is the inclusion of a pre-formatted SRAM content for games possibly needing it (iirc, Ken Griffey?)
but that just needs the loading procedure to be adapted and the softlist could already 'preserve' them (just add the <rom> inside the sram <dataarea>, like it's done in MAME with pre-formatted EEPROM settings)