The criteria: "A lead object that is blocking a direct path between me, and an item that fits criteria X, Y, Z."
The result: The direction of the nearest item that fits criteria X, Y, Z that is being blocked by a lead object.
Does the criteria lead to the result, given that you read the spell description of locate object literally?
Locate Object can be blocked by lead, but it can also locate lead itself regardless.
Best Answer
I'd have to say no ... for a few reasons:
I would, however, allow you to locate the nearest block of lead, since as it states later in locate object
...which is simply "Find the nearest hunk of lead." OK, sure. :)