Sneak Attack Against Those Normally Immune?

[BardicDuelist]

So as to not derail the thread: The dungeonscape thing, a wand of the spells listed above, etc. work really well.

For somthing else:
In a two person undead campaign with a rogue, we created an item that lets you see pockets of concentrated negative energy on undead (which is what presumably animates them), and if your weapon was holy or dipped in holy water, you could use sneak attack (from a fluff standpoint you were disrupting those vitals).

You could do the same thing against constructs by seeing pockets of concentrated magical energy (which presumably animates them). The weapon would have to be magical.

Goggles, lenses would probably be the best slot to use. I admittedly never figured out a cost for this item, as it would seem silly for the rogue to want to sell it. I would guess it would cost w/e it would cost to have a continous 1st level spell.