Ikea Billy shelf - shorten shelf boards?

hi guys,
I'm thinking about treating myself to a Billy shelf to put my TV on...
now I wanted to know if it's possible to shorten a shelf board and install drawer slides so it can be pulled out.
how much weight would it still hold??? because I want to put my PS3 (6-7kg) in there and it needs a lot of FRESH AIR :D
THX in advance

hi guys,
i'm thinking about treating myself to a billy shelf to put my TV on...
now i'd like to know if it's possible to shorten a shelf board and install drawer slides so that it can be pulled out.
how much weight would it still hold??? i want to put my ps3 in there (6-7kg) and it needs a lot of FRESH AIR
THX in advance

good day. which billy shelf exactly do you want to use?
do you have a photo?

I mean the billy bookshelf