Let's say you happen to be a mathematician, and your spouse is also an academic and in a humanities field in which there are very few jobs advertised. Assuming that you can convince universities to hire you on a tenure-track level, what are the chances that they will be able (or willing) to create a position for your spouse? If you already have a job that you are reasonably happy with, is it at all reasonable to apply to positions where there is nothing advertised for your spouse in the area in hopes that you can arrange something for them if you get a job offer?

I'm mostly interested in the US and research I-esque jobs, though I would be happy to hear about the situation in other countries.

EDIT: Since Yemon asks, here are some examples of answers I would like to see:

• specific anecdotes about this happening or failing to happen. I don't want to violate anyone's privacy, but presumably some of these can be anonymized or are a matter of public record.
• comments from people who've been in administrative capacities in departments/on hiring committees about whether this is something they would even attempt to arrange, and whether they've had any success with it in the past.
• obviously, actual data on how often this happens would be great, but I have trouble imagining it exists, at least specifically for mathematics.

I'm failing to see why Andrew thinks that no one will be able to surmise anything from a long list of anecdotes. Obviously, it would be better to have data, but when trying to figure out what one could even hope to ask from a hiring committee, knowing what has happened in the past is very valuable information.