That's just the kind of thing you can do relatively easily with a plugin.
Since VA now supports wildcard, you could define a command that responds to "Search for *", make that execute a plugin call, and in your code parse the whole command (which you can pass to the plugin with the already existing tokens) to extract the desired {term}, maybe even the "on google" part, if, say, you want to use different search engines for the same command), and finally launch the proper query
Keep in mind however that non-dictionary/not know before hand words (like anything you might say as {term} and even the word "google" itself) are hard to catch properly by the engine, so while the command while fire because it will recognize correctly the first, fixed part, you are gonna have, in many cases, a lot of garbled stuff in the remaining string.