Low Cost ARM + FPGA Computer?

What if there was a low cost, small, power efficient ARM processor based computer with a reasonable FPGA attached to it?  I'm thinking 600 MHz ARM Cortex with an Altera Cyclone4.  What if this board could be powered by Power over Ethernet (PoE)?  What if the ARM processor could reprogram the FPGA over JTAG?

As long as the interface between the ARM and FPGA was fast enough, the types of things this computer could do would be rather vast.  Some computations are much faster in "dedicated" silicon (an FPGA isn't really dedicated silicon, but for the money it's close enough) than in general purpose processors.  For example, crypto processing is dramatically faster in "dedicated" silicon than in a general purpose processor.

What if you could have 47 of these little ARM + FPGA computers plugged into a 48 port PoE switch? (Or 15 in a 16 port switch?)  The switch would power them and allow them to communicate.  A desktop PC could coordinate the operations of the boards and feed each one the data for computations.  It'd basically be a mini cluster of FPGAs that could scale and be affordable.  It'd also be easy to wire compared to normal computers as there's only one wire per ARM + FPGA computer (the Ethernet cord provides both communications and power).  And if you can't afford to buy a lot of nodes, you can just buy a few and expand when you can afford it.  And if newer versions come out, you can add them to your cluster.

There's lots of software out there to coordinate clusters of computers, this is nothing new.  But currently a lot of the crypto busting computing power that's available comes as PCI-e cards with very expensive FPGAs attached.  There's also the problem of scaling a PCI-e based solution, once you run out of PCI-e slots, you need another expensive computer, and you'll still need coordination software and expensive networking if you have more than one PC.

If the ARM + FPGA computer could cost around $100, come with great documentation and libre licenses for the software and FPGA code, plus offer professional support, I wonder if anyone would buy it...