Could use a multiplexer to select the right "chip selects" => 4 lines to select one of 16 memory banks!
I looked at 16 pin 3:8 decoder chips and decided for fewer than eight chips I would directly handle chip select.
For eight or more chips a decoder makes sense. I bought several 74HC138 decoders and may try to get the 16-DIP decoder and eight SRAM chips on a proto shield. For 16 SRAM chips you need a 24 pin DIP decoder so a custom PCB would be nice.
For larger memories, the 8 MB RamDisk pito is using http://www.rlx.sk/en/storage-boards-memorystorage-boards-memory/2559-ramdisk-8mb-8mx8-8mbytes-with-8bit-parallel-access.html looks good.