Now that Saradush has been destroyed?

You can buy scrolls in Amkethran. Lazarus in Saradush escaped the destruction and set up shop there.

There's also a merchant in that wilderness area - I dont' know if he has scrolls though.

I don't think the merchant has anything really useful (aside from an Ioun Stone) but he's handy for selling your items to and building up your cash.

There's also the knight on top of Watcher's Keep who sells some pretty decent items.

The arcane place in that desert villiage just has a cranky little gnome that yells at you but no man selling scrolls. I want to get imprisonment and time-stop to defeat Draconis in his dragon form.

You get the scrolls from the other guy with the gnome, standing near the furnace & pipes - he's easy to miss, but he's in there.

You need certain items from Draconis - I don't think imprisoning him will get you them. Time Stop should help, though.

I defeated Draconis. Not sure exactly how but I launched every spell at him, ran around with every fighter and finally I used limited wish to turn Nalia into a mind flayer and then turned my main character into the slayer and he just went down somehow. I didn't get any experience for him though.

I don't think the merchant has anything really usefulIIRC, he has Boots of Speed.

Are you sure? I don't remember him selling Boots of Spell. I know the innkeeper in Saradush has a pair and Lazarus at the Arcana Archives but I don't think this merchant has any.

The merchant in the wilderness map does have spell scrolls, even up to level 9. Black Blade of Desaster and such.