Any amplifier can be used just like with a speaker. Something like a iNUKE1000dsp has adjust-ability such as delay for time alignment, low pass frequency settings, power limiter... Look around this site, many threads discussing shakers and what others used for amplification. Many other user comments all around with people discussing their method of amplification and system setup. I would some day like to try a shaker system myself.
Edit: Using a bridged amplifier with two 4 ohm can be wired either 2 ohm or 8 ohm, or could do it 4 ohm stereo. You can look at any speaker wiring diagram and it will work the same as with the shakers.