There is really a model for everything. BBC reports the results of a study that states that there is a link between sleep position and personality. The most common sleep positions are:

BBC NEWS | Health | Sleep position gives personality clue via kwout

The personalities according the position are:

• Foetus: tough on the outside but sensitive at heart
• Log: These sleepers are easy going, social people who like being part of the in-crowd
• Yearner: are said to have an open nature, but can be suspicious, cynical
• Soldier: are generally quiet and reserved
• Freefaller: Often gregarious and brash people, but can be nervy and thin-skinned underneath, and don’t like criticism, or extreme situations.
• Starfish: These sleepers make good friends because they are always ready to listen to others, and offer help when needed.