valve seals?

[Gorman, Ken (PA62)]

Looking for some list wisdom..

Symptoms: 
a. 91 200TQ goes through about 1/2 quart of oil per month 
b. puff of smoke every time when car is started
c. car has 176K miles

At first, I thought it was a crankcase ventilation problem - I replaced the
crankcase breather hose, but still have to top off the oil periodically.
I'm thinking it could be worn valve seals.  Does this sound reasonable?  How
could I confirm this?  What else should I look for?  If it is valve seals,
is this a big job?  What would a ball-park cost be?

Thanks,

Ken