Those cheap electric coffee/spice grinders will certainly do the trick,
but care must be taken to avoid powder.
If you want to check out keif boxes go to ebay and search for "pollen box"
As mentioned, the pollen box was my other solution, but I know very little about them, which also would lead to wanting more of a knoweldgeable reccomendation on where to go in that regard, if I do go that route (I could see myself doing it though, grinding up a bulk at a time and then dumping into the pollen box for sifting/storage).
@spincut, I believe @Vitolo, praises his Krups coffee grinder for fineness, maybe he'll chime in when he gets the time.
I use a 4 piece SCS as my main driver. I spear my bud to the lid, and press the 3piece portion to it sideways, spin back and forth, then free spin both ways until I feel no resistance. Only then do I turn it upright to let it fall through the holes spinning and tapping the sides. I end up with a fine grind that so far has worked great with my Plenty, Solo and Silver Surfer, but not quite fine enough for MFLB.
I do the same sideways thing with my space case, and it does work "ok", but yeah, not ideal, plus I do sometimes worry about kief being dumped back into the main chamber (less of a problem now that it's gotten some use though).
And yeah, the "powder" problem is what makes me wary of anything coffee grinder-esque. I don't imagine the SCS works any different or better than my space case model (in fact from what I can see they seem of very similar designs, except perhaps the coating and titanium option I got?).