Pre-requisites: Medatitive Arts III, Tinkering V and the as discussed in other ideas high level Carpentry.
Result - gives the owner the ability to increase the storage space of items such as bags, racks and cupboards in houses. Level 1 gives a 3 space increase, level 2 gives a 6 space increase and level 3 gives a 9 space increase. Level 3 could also give a theoretical extra room in houses for increased storage.
Don't applaud, just throw money.