In addition to sales, I'm a rental agent with Coldwell Banker in Pittsburgh, and our property management division is also able to help locate rental homes for you. As you've found, it can be a frustrating search online, because there's often not much that comes on and when it does, it often goes off quickly. I'd be happy to help you in your search, and know there are at least a few options in Mount Lebanon right now. Feel free to contact me at firstname.lastname@example.org and we can discuss your other needs and price range.
you can also visit our page below, an easy and convenient way to search for rentals (or homes for sale) in areas of your choice.
Realtor.com does list a few 4BR homes for rent right now. More will likely come on the market when the school year ends.
I can also get you in touch with Northwood Realty Services relocation department to help you in your search.
If you'd like a list of homes for lease in this area and similar areas. Shoot me an email. A lot will be coming available with the school year ending. Just let me know the time frame you're looking to relocate. Also, if your in town in between the time you relocate, you can also stop by our office we'd be glad to help.