embedded telemetry receiver

We have a need to a circuit that can accept a data and clock signal at up to 12 megabits/second and make the data available to ingest by a processor.  I strongly suspect that this has been done a few times.  We also need to build this in as an embedded system, no memory devices other than RAM and the code burned into ROM.  My first thought is to use an ARM (or something similar) on a prototype board such as the ones that various companies sell to demonstrate their CPU.  We would then connect a programmable IC to clock that data in and let the processor grab it, maybe 16 bits at a time.

I can and do write code to extract what we need from the stream, but have done nothing as far as the hardware to translate from a serial bit stream into something the CPU can handle.

Where might I find the documentation I need on doing this.  Have you any suggestions?