In-car, I'd guess the turbo could be best inspected by removing the air box and turbo-inlet pipe to feel the compressor for any bad shaft play (in or out, up and down). You can try removing the down pipe to see if anything "important looking" fall out of the turbine side.
Either side should be noticeably bad if the car belched smoke and then died. Additionally, if the turbo's death was particularly explosive, shrapnel from the turbo itself could've shot back into the engine and damaged other parts as well.
By the way, was the cam belt in good condition still when you got the car?