MyWarcraftStudio was a tool made by Linghuye.
It was capable of exploring models, creatures and much more in early WoW versions.
Displaying and saving textures, even opening DBCs.
Sadly it does not seem to be compatible with custom MPQs.
But it works perfectly with Vanilla and the TBC alpha. It was designed for alpha version 5665, but it also works for versions close to it such as 5610 and for vanilla.