Oil "wick" eh?  Never had a name for it, but it's an old trick.  I first
saw it used by an old Viet-Namese cabinet maker.  It's nothing complex 
at
all, just some cloth tightly rolled up so that you have a cylinder about 
an inch
in diameter and about three inches long, tied up with a bit of string
so that it doesn't get loose or flex.  Anybody else here familiar with
the "Tibetan almond stick"?  It's like one of these.  In fact, one of
these might work well.

I noticed that the old cooper in El Tonelero used one on the bottom of
his plane -- remember that video that was posted here a few months back?
He used "manteca," essentially lard on his.  The Viet-Namese cabinet 
maker
used pretty much whatever oil was at hand.  Mineral oil works fine.  I
found this system very useful for wooden planes, especially when doing a
lot of planing on resinous woods like sugar pine. It eliminated any drag
on the planes.

Linseed oil doesn't seem to be the best choice to me since it oxidizes
and will become hard, which will make your wick hard in time.

For metal bodied planes I'd use wax.  Another old trick is bee's wax.
Used to be you'd find a chunk of bee's wax in most carpenters' tool
boxes.  This was mostly used on their saw blades, and it really helps
the saw slide through the wood.

I keep both an oil stick and a chunk of bee's wax in the small tool
box I use at Sutter's Fort.  Done that for about 30 years now.

Back when I was working with the Phoenix Planing Mill, we would
use a big chunk of paraffin wax on the cast iron tops of the
table saws and shapers to keep wood sliding freely. I imagine
that a cloth stick and a bit of Johnson's paste wax might work
for metal planes.

Mike in Sacto