Implemented in the inventory so far:
Switching the inventory lines (top 16 and bottom 16) for easy access to all 32 slots using the 16 slots hotbar, clearing inventory without having to open the console and running /clearinv.
Missing: Search/Filter (even if the icon already is active *g*), pagination, not showing empty space if there are too less nodes on a page.
Also: Now using only own placeholder textures (plus the built-in menu icons from the engine).