FIFOs are hard to find - I wanted some for audio for a past project, they were hard to find and pricey.
The FIFO is implemented on your arduino. You do not need an external one...
With 1284p or Due you can implement large enough FIFO buffer for even your audio streaming
With max latencies of 50msecs and 14kB of 1284p ram you can go up to 280kB/sec sustained writing speed to the sdcard.. (provided your 1284p or Due is fast enough)
PS: I ran 333samples/sec (100bytes a sample) with 1284p without a single overrun to a cheap sdcard recently..