Did you make one? If did and you want to get it appraised, it would probably be best to show pictures. Price can really vary depending on how well it's put together and who is in the market to buy one. A PS3p with an HD screen and a CNC cut case is obviously going to go for a lot more than if someone slapped a PS3 and a 480i LCD screen into a breifcase. Sorry to not be that helpful, but it's a pretty hard question to answer.
A really nice one made by Ben went for $9,000 on ebay, not sure if the winner actually paid thoughhttp://www.techeblog.com/index.php/tech ... -hits-9000
This guy says he would sell his for $2,000http://www.youtube.com/watch?v=ikmKvgUU99k