Originally Posted by Powerlord
It's possible to force ragdolls to be done on the server side... I think. At least there's a DataMap for it: m_bForceServerRagdoll.
Edit: This datamap may only exist on things decended from CAI_BaseNPC, though.
Edit2: Nope, it's on the CTFPlayer class in TF2 as well, so it's likely part of CBaseCombatCharacter.
There is way too much physics data in a ragdoll for it to persist serverside. As it is, just 10 or so dynamic props bumping into eachother can spike the server. Ragdolls often have 12 pieces or more, which have more complicated relationships (hinge/constraints). Probably they are disabled in mp, because the server can't proccess that much data. Player ragdolls (tf_ragdoll for example) are simulated clientside.
You could try https://developer.valvesoftware.com/wiki/Prop_ragdoll
But again, its a very bad idea.