There are lists out there on infertility websites (e.g., Resolve) about companies that offer infertility coverage. However, this list is ever-shrinking, and given the current economy, I believe that it will continue to get smaller before it gets larger.
In terms of calling prospective employers, I honestly don't think that's a great idea. Unless you're pretty far along in the process of interviewing with them, I don't think they'll talk to you about the details of their health insurance plans, and if you are, you're giving them a heads up that you plan on potentially taking lots of time off of work to undergo fertility treatments and costing them money by using your health insurance benefits (they want employees who are healthy and won't be using up their expensive health insurance). Also, the policy they offer today, may not be the policy they offer tomorrow. I've had employers change the details of their health insurance policies drastically come open enrollment time. And not small employers either.
Having lived in a state with mandated infertility coverage and having used 4 different health insurance plans over the course of ten years and STILL having spent close to six figures out of pocket in spite of the "mandated" coverage, these are my suggestions, and I hope that others will chime in with more:
1) look at the states that have mandated coverage and CAREFULLY read what they mean by "mandated"; so far, MA has the best mandated coverage in the US with the fewest loopholes. You can get this information from the Resolve website.
2) Depending on what industry you're looking at, try to go with the big, international employers that have offices all over the world. They tend to have the best benefit packages because they can absorb the costs across a large number of employees. Big consulting firms are GREAT for this. Generally, the smaller the employer and the older the principals/partners/owners, the less likely they'll have good (or any) infertility coverage. Why? Their insurance rates are already high because of the age of the partners and they aren't going to pay for the extra coverage for infertility for the younger employees. The catastrophic medical coverage and other higher end medical coverage will likely be great though.
3) If there is a benefit you want to ask about, it's a Flexible Medical Spending Account. What insurance won't cover, you can realize tax savings on by using a flex account with.
4) Look at jobs with the City, State, and/or Fed Govt in the states w/mandated coverage. They often have good infertily coverage and no loopholes.
That's it off the top of my head, but if I think of more, I'll post it.
GL!
ETA: Congrats! My ds is a July baby and an absolute joy.