What is the enhancement in mind? How should it look and feel?
Add a filter to tradeskill list (in Skillet this would be a new checkbox beside the "Hide trivial" checkbox) based on how many of the end result item a character + his alts (exclude guildbank) has.
Checkbox would read "Hide item if more than X in possessions", X being configurable (slider or other).

Please provide any additional information below.
First of all, I *love* LSW, easily one of the thing that makes me saves the most time since the invention of [Sliced bread].
Let me tell you a little bit how I use LSW, I use it with Skillet and a neat addon addon based on Possession data which adds to the tooltip how many of a particular item alts + character + guildbank has (it's called WhoHas).
My auction niche is Glyph selling, which means I have in stock anywhere from 80 to 120+ different glyphs. What I try to do is maintain my stock to a minimum value of 3, each time I restock I do this :
- sort tradeskill by ItemValue
- for each recipe which is above 10 gold I hover on item, check my stock, if it's under 3 I craft what is missing

This enhancement would allow me to save precious time not having to hover on item, I would have directly the craft list I need to do in order to restock.