It may be worth having a look at OID 188.8.131.52.184.108.40.206.1.3.1
This presents a table which shows details on each switch in the stack, including a "moduleStatus" field. Exactly what this would do in the event of a switch going down, I am not sure; but it may give you something to start with. An alternative would be to just poll for the presence of a particular port on each physical switch in your stack and fire off an alert should that port become unavailable.
hi, thanks for reply, OID polling with status on map still isnt available, hence this post for better polling.
also polling an interface on a switch stack, will give false alerts