Yeah, I think people tend to be more price conscious when buying kids clothes because of the short time period they actually fit them. As a result, it can be hard to find higher end features.

I personally would look for a poncho. You could get the disposable (Coughlin's or similar) ones for a couple bucks (or less). I also found this with a quick search on Amazon:

https://www.amazon.com/Charles-River-Apparel-8709-Pacific/dp/B0057NYC04/ref=sr_1_12?s=sporting-goods&ie=UTF8&qid=1490032561&sr=1-12&keywords=kids%2Brain%2Bponcho&th=1&psc=1

It seems a little more durable, though i have no first hand experience.