If you find a search widget that uses the web, like the eBay one, I think there would only need to be a few lines of change in the html or js file to make it into an acronym finder widget. Then just polish up the graphics.
I was looking briefly, but duh, I tried the dictionary widget, which I should already have known was not a web search and isn't any good. But one like the eBay widget or the package tracker widget or something like that -- the simpler the better.