<< Normally, the pipe is a bright white and it will stand out like a sore
thumb on this house. >>
Should it become necessary to run an outside vent extension, consider using
electrical grade PVC which is usually gray in color and is UV reistant. If that
is too garish for your situation, a good paint store will have PVC specific
paint to match the hous color. A climbing ivy could cover it as well.
<< Also, given the installed pipe, how much is this likely to cost either the
current homeowner or me? >>
$500...$1000...$1500..can't be estimated from here with any precision.
Whatever, good luck.