you should check the compression ratio of the cylinders or get someone to do it for you it could be the rings. i have a similar problem with my turbo it gets really smokey when warming up but when it warms up its fine .

if its turbo check the inlet pipes for oil or even run the car with the turbo pipe diconnected if theres no smoke when ya do that the turbo should be ok.

it could also be the valve stem seals did you get them replaced when you got the head gasket done ?