I think you can also get LP sleeves and outer jackets from Red Trumpet, dccblowout (aka Better Records), and Elusive Disc. Here are the links:
http://www.redtrumpet.com/
http://www.dccblowout.com/
http://www.elusivedisc.com/
http://www.redtrumpet.com/
http://www.dccblowout.com/
http://www.elusivedisc.com/