Originally Posted by
Darrin
Sounds somewhat like a Rod of Lordly Might. However, those things are hella expensive...
Fortunately, there's a cheaper knock-off version called a Rod of Surpises (6000 GP, MIC). Pressing the buttons allows you to change it into: a javelin, kama, longspear, quarterstaff, scythe, shortspear, short sword, or spear. This covers #1, #2 (if you count a double weapon as two weapons), #3, and #4 (uh... sorta... you can throw a javelin/spear).
What an odd set of parameters... how exactly are you determining familiarity? I imagine this would only be an issue with exotic weapons.
You lost me here. You want an enchanted weapon that turns itself into some other kind of non-enchanted weapon? Hmmm. You want a non-magical morphing weapon? Aha!
Shapesand (Sandstorm p. 102). This can do #1 through #5 with just a Wisdom check.
I don't think shapesand can do Masterwork quality. This would be a moot point with a Morphing weapon. However, a Morphing weapon can only change into another melee or thrown weapon of the same size and type (light, one-handed, or two-handed). You couldn't change a Morphing Greatsword into a throwing axe or light crossbow, for example.