Man, I just went through trying to find the Lycra shoe covers too. Very few people seem to make them. Like you, I just wanted a lightweight pair to keep the road grit off in the rain. I found these:http://www.competitivecyclist.com/giord ... r-w-zipper
They sure are expensive though ($45 for a couple pieces of Lycra!). That is about as minimal a logo as I could find.
I ended up getting these due to the price difference:http://www.giro.com/us_en/ultralight-ae ... cover.html
Bigger logo but I found it for $26;
Castelli makes the Aero Race DM which has their typical flashy graphics, but a higher cut; also a standard Lycra shoe cover with less flashy graphics
Sugoi makes one that is a bit more water resistant supposedly, the resistor aero.