if the head was "badly warped or cracked", it wouldn't be drivable.
yes, mayonnaise under the oil cap is a symptom of head gasket, but
usually it's a /lot/ of mayonnaise, not a little.  a little is not
getting the motor hot enough like curly says.  check/replace pcv and
keep driving until "symptoms" get worse.  do /not/ warm up engine on
driveway.

I have a 99 honda civic with a d16Y8 sohc engine with vtec (its actually an
acura 1.6 el, but for simplicitys sake, we'll call it a civic since its the
same thing).  and I have milky tan\white colour stuff (gunk i guess), in the
head (under the valve cover).  This is a symptom of a head gasket leak going
from the coolant to the oil, but I dont seem to have many of the other
common symptoms!

here is a list I made of what i know

-thick tan coloured residue in the head
-oil looks normal on dip stick
-engine is not overheating
-the engine runs and idles normally
-the engine hasn't lost power
-spark plugs appear normal (somebody compared the plugs from there intega to
mine)
-cant smell coolant in exhaust gases (at least I cant)
-no bubbles in coolant resivoir with the engine running (should I check in
the rad cap with the engine running?)
-looks like there's oil in the coolant but the coolant is not milky, its
bright green.  however, when I take the overflow hose out of the resivoir,
coolant drips out of the hose and when it hits the coolant in the resivoir,
i can see a little bit of black liquid which dissolves into the coolant (is
this oil?)
-the exhaust dosent look too white (from burning coolant), but it IS winter,
so it might be hard to tell
-The coolant level dosent seem to be going down (if it is, its too slow to
tell after just a few short trips)
-my PCV valve could be clogged, I dont really know (which would cause
condensation in the block\head, leading to the residue in the head), but
given that it looks like there is oil in the coolant, Ii think this is
probably less likely the problem.

What do you think, is any further testing nessecary?  I would like to stay
away from spending money on any testing equipment if possible, but basically
the only two problems seem to be blown head gasket, or clogged pcv valve..
and i guess a possibility of a badly warped or cracked head.

thanks in advance

Phil