Rings might not necessarily be gone.
If you have alot of positive pressure in the crank case etc you can blow out the dip stick.
Where are the lines from the cam covers going? If they are very restricted or blocked off you will do what you have described.
Also, are you using alot of oil?
Check the PCV that is in the inlet manifold, there is a line from the engine cover to the inlet, the valve could be blocked, or someone even blocked off the factory pipe that goes from the turbo side engine cover to the turbo inlet.
All else failing, take off the hoses from the engine covers and take it for a drive, if it still blows out the dipstick then you will want to do a compression test.
If you are still unsure ask a mechanic for a Compression test and perhaps a 'Leak Down' test may give you more answers (Although its probably for more head gasket \ leaks into the compression chamber related issues).
I would also recommend Status in Dandenong, but I am just Biased.
Everyone on that list is a reputable shop also.