Michael
I just cloned my sucessful site
KALEIDOSCOPES TO YOU - 1000's of Kaleidoscopes In Stock - We Sell Kaleidoscopes & Marbles. to
MARBLES TO YOU - 100's of Handmade Contemporary Art Glass Marbles In Stock - FREE UPS Ground Shipping on Orders Over $200.00 -Shop Online
I was concerned about many of the same things you were about rankings etc. I cloned in april of this year so the school session is still out. but over all i am happy I did clone. I am releived to find out site A s rankings will not be hurt by site Bs duplicate content. I have seen some good placement of the new site so in effect i am helping to stop up the first 10 spots in natural rankings with another one of my sites.
Karl