Early in the game, I found someone with glass arrows for sale, stocked up, now I'm out and can't locate the vendor: is teh stock limited, am I overlooking something, or was it a fluke of some sort that I was able to get any at all?

Oru

Have you tried the fletcher in Vivec? I think she's in the foreign quarter and she usually sells everything. If she's not there, then she's an official add-on from the morrowind website.

I think the legion armorer in Ebonheart sells them. The supposed master armor that isn't.

Somebody Selvayne....the trader in Tel Branora has a limited amount.