SRAM Red 11-23 10 speed OG-1090 cassette, uber low miles, includes alloy SRAM PG 1070 lockring. Same lockring as a 1090, just different engraving. $60.
http://www.flickr.com/photos/bicycleparts71/10684547085/
http://www.flickr.com/photos/bicycleparts71/10684593626/

SRAM Red 11-26 10 speed OG-1090 cassette NEW, includes alloy SRAM PG 1090 lockring. $120.
http://www.flickr.com/photos/bicycleparts71/10684593506/
http://www.flickr.com/photos/bicycleparts71/10684547175/

Rotor Q Ring, 54 tooth outer, NEW
Rotor Q Ring, 42 tooth inner, barely used. $150 for both chainrings.