would anyone by chance know how to create a spell merchent that uses PSB as an invintory? all known spells in game including those added by mods etc? I would sort of like this as a resource for convinently buying spe3lls i cant get anywhere. (I.E Death Knell of Sithis) so is this possible?

Anything like that is fairly simple. Just make a merchant that can sell spells. Open up the magic > spells tab, select all the spells there, and then drag it into the NPC's spell tab. If you can't drag them all, you may have to drag one, or a few at a time. Spell vendors sell spells they know.

This will however not work for any spells which are added by mods, unless it is from another loaded .esm. Only spells may be learned, powers and lesser powers cannot be learned. Additionally, trying to use a vendor with that many spells may create issues when you try to learn from them. It might be more productive to just include most of the hard to find, and useful spells on such a vendor. The spell prices may also be wierd because they are based on magicka costs, and many non-normal spells have excessive or impossible costs.

I remember this thing "Teach Spell to others which was added via script is there no script that provide an NPC spell merchent with PSB?