Spells from vendors

[Othesus]

No, I'm pretty sure this isn't possible with a UI mod. If you use comparison tooltips though, you can compare the spell for sale with the spell that you already know. Look under Options - User Interface - Tooltips. I use the option where the comparison tooltip pops up when you hold down control.

I hope that's what you're looking for.

Othesus - Dirge - Lucan DLere
Vaspar - Fury - Lucan DLere