Simple Q&A D&D 3.5 (by RAW) XXII

[willpell]

No the Powerful Build ability mentions no such option. Moreover a scimitar one size too small would make it a light weapon, but you would get a -2 for using a weapon of inappropriate size.

A Medium scimitar, though too small for a Large creature, is not too small for a Medium creature with powerful build. So it is usable normally, but I guess it would always be a one-handed weapon. (Of course if I'm reading these rules right, Goliaths can't actually use Two-handed weapons which are sized for Large creatures, since they would become heavier than two-handed weapons, even though IIRC several example NPCs have Large greatswords and the like. So if restricted to using Large 1-H weapons which can only be used as 2-H, or Medium 2-H weapons, or Large Light weapons which are used as 1-H, or regular Medium 1-H and Light weapons, goliaths are a bit less exciting than if they can use Large 2-Hs. I may houserule to the contrary just for Rule of Cool reasons.[/thinkingaloud])

A 351(e): (Also see p75 of the 3.5 Main FAQ).

I do not know where this is.

For clarification, wish allows you to create a magic item. The following text is found in the SRD under artifacts:

The wish spell is mortal means. The DMG has some additional "fluff" text about artifacts in general which confirms this as the rule for all artifacts.

The "common" part is debatable IMO, as a Wish is probably "uncommon mortal means", but that's me nitpicking the text; RAI is almost certainly that you can't Wish for artifacts, though the proof is not ironclad IMO (but then so little of 3E actually is).