As far as I know, there isn't anything made already, but I don't see why you couldn't just modify search.asp to include the appropriate code. I don't have a copy of the forum with a calendar MOD available nearby, but in search.asp, you could add something like this (don't forget to add the code to check whether events are enabled and all that jazz):
This code is all from a fresh download of 3.4.06, so your line numbers may vary.
At line 724 add the follwing:
That and the surrounding area should look like this:
Then just add the check to the SQL string at the top.
Around line 293 add the following:
That and the surrounding area should look like this:
As I said, I don't actually have a copy of the Events Calendar MOD in front of me, so I'm not 100% sure the field is called "IS_EVENT", but I think it's something similar. At the very least, this should help you move in the right direction.
As always, back up your file before doing this.... I mashed it up in a few minutes, so it's untested and could well contain errors.