Cantelever Kayak Rack?

Got a surf ski on order.

Would like to move from this: http://tinyurl.com/2l3mve
to an outdoor version of this: http://tinyurl.com/3d2way

The idea being to minimize the footprint and make mowing the lawn
around it easier.

My first thought is to dig two post holes nestled into the line
of forsythia in the first link, put a vertical length of schedule
40 PVC in each, pour concrete, saw the PVC off flush at ground
level, and then insert the rack's vertical members into the PVC.

But what to use for the rack's vertical/horizontal members?

Seems like galvanized plumbing pipe isn't all that structural,
the threads at connection points would be rust-prone, the inside
probably isn't galvanized,  and it wouldn't be very flexible in
terms of adding/relocating cantilevers.

Wood seems like a workable fallback position - albeit subject to
rot as water ac***ulates in the PVC it's inserted into (there's
really no hope for drainage holes bc the soil is clay and shale).

Some kind of galvanized square stuff?   They use something like
that for traffic signs around here, and it seems tb holding up
pretty well.

Or am I missing some solution that's simpler than the holes in
the ground - yet minimizes the footprint?

My biggest reservation is that I'll be creating a situation where
the rack's vertical members are sitting in a pool of water that
never goes away.

Anybody have some insights?
-- 
PeteCresswell