What you do is buy one of the USB asic devices (like the AsicMiner USB block eruptor) and plug it into your Raspberry Pi. Pis do have a USB port, right?
yep it has a usb port- but will probably need to be powered with a usb hub.
I guess what I was really asking is if it was still worthwhile to buy one of these USB bots and if so what is the best for ROI