Personally, this seems like a lot of heavy lifting and manual labor, and the effort involved seems to outweigh the costs of commercial tools already available. For example, SQL Sentry's Event Manager is a very affordable option, and it does everything your solution does and more... including elaborate event notifications not only for failed jobs but also job runtime thresholds, event chaining and a very nifty Outlook-style calendar view that gives you a graphical view of your job schedules across many instances.

I'm usually a total advocate for reinventing the wheel, if you are going to add something very powerful that isn't already available in packaged solutions (or if you really want to learn the API, catalog views, DMVs, Agent subsystem, etc). In this case I suggest your readers take trial versions of available packages for a spin before going too far down the "roll-your-own" road. At the very least you will see what you might want (and might not want) when you build your own solution, but more often than not you will realize how complex it can be to go that route, and that you will actually save money by spending money on a ready-made tool.

This is a classic argument that I have been having for ages. Back when ASP was a popular web language I used to argue until I was blue in the face with people who wanted to write their own mail or upload component, to save the $99 or $150 of the premier such component already available to buy on the spot. For most of us, if it takes us more than hour to build such a component, we're already behind. Then there is testing, debugging, performance testing, etc. etc. All of which you get for free when you have a reputable vendor behind the product.