WARNING! These are from an RV point of view. If that makes you spit and foam at the mouth, please do not go to the link.
A few links. These may give you ideas on things to do. While they are for manufactured RVs, much of what you will see can be adapted to skoolies or start you thinking. Some are just neat like the PVC ice packs
and the PVC Water Accumulator
both of which we will most likely do, the accumulator tank because the pulsing is irritating and the ice packs because I currently use a partially filled water bottle or a Nordic ice pack, both of which have developed holes and leaked (ick). We travel with no power to the freezer and refrigerator and rely on ice packs to fill the refrigerator if it's not full enough.
Other entries are very practical like the Genturi
or the RV door & paper towel storage
. Don't forget to check out the remodels on DIY too.
For those who are interested in building their own bunk beds and sofa beds
this site is a good one.