The "What's New in 8.5 and 8.5.1" help doc indicates that you can also add a website as a search bar engine just as easily as a Notes view:
I looked and I looked, but I couldn't find the Widget option to do that. My wife says that I can't find things even when they're sitting right in front of me, so honestly the option might be there in a very obvious place and I simply didn't see it. However, since I couldn't see how to do it, I decided to write a plugin to add a website search for me. Here's what it looks like:
When you do a search with it, it will search the following sites simultaneously:
Here's a short demo video to give you an idea of what I'm talking about, if none of that made any sense. I made that Camtasia video before I added Chris' blogger search engine, but you'll get the gist.
If you want to download this plugin and use it yourself, just go to the SNAPPS Widget Catalog, click the "LDD Web Search" option, and follow the instructions. It installs just like any other widget, but you won't see anything new in your sidebar after you install, just a new option in the search bar. And you'll have to restart the Notes client after install too (sorry, not my fault).