Additions/Modifacations I have added to the PUP
Please feel free to send me an email if you have questions or comments:
john@camperjohn.com
Standard bath caddy used next to the sink for additional storage
By the sink
I wanted something handy next to the sink for a dish towel, hand soap, etc.  So what I landed on was this standard bath caddy from Bed, Bath and Beyond ($15).  You can see I have it going just behind the bench cushion and then extending to the ceiling.  It works perfect.  The baskets are turned towards the sink and does not interfere with anyone sitting on the bench.  The hieght of each basket is adjustable.  I put the one with a towel holder in the middle.
Extra shelves for storage
I really needed extra shelving for food and goodies.  I researched a lot and even considered making my own.  However, I came across these expandable/stackable 'drying shelves' from, once again, Bed, Bath and Beyond.  They are spot on.  I can expand them from side-to-side and stack three high (only two shown - one large and one medium).  I have two large on the bottom and one medium on top (so as not to make it top heavy).  The base legs have non-skid tubing on them so they don't slip.  Oh, and did I mention, the legs fold under for perfect storing while not in use.

Cost, about $12 for the large and about $9 for the medium.  I have included links to product web site if you want to see more details.
Links to items mentioned above:
Sink caddy
Shelving units