I would also recommend staying at 48V. There are for example hot water heaters at this voltage and this standard is gathering momentum. Propulsion for both EVs and EBs (electric boats) are now invariably 48V and are going up by a multiple of that to 96V, 144V, etc. I believe home DC standard fed by solar panels includes 48V. Most likely you will be able to find appliances at this voltage.I would like to see that picture. Upon further review it seems like it might just make sense to leave the 48 volt modules intact and use an inverter that accepts 48 volts. Considering all the 48 volt modules have posts and would have intact BMS leads it might just be the way to go. As I learn more about these batteries and the lithium world I feel more comfortable breaking away from what is normal for the lead acid 12 volt world.
Note that 12s is a bit anemic for 48V and ideally you want to be 13s or 14s. For my projects, I am going 14s. http://www.diyelectriccar.com/forums/showthread.php/18650-13s10p-project-48v-x-34ah-188618.html