I was able to write an ACTool script that basically checks your tavern for purple heroes once every hour. Not 100% sure it's working perfectly (due to the rarity of purple heroes) but it looks like it is, at the very least. My experience with this game and scripting leaves me to say it's very... patchy, and the bugs, lag, and oddities (like "Click OK" gumps that don't disappear unless you click them, and can randomly appear due to guildmates being attacked, you being scouted or almost ANYthing) make it difficult to script successfully.
Still, it's possible, though anything worth scripting would only be valuable for people who play this game well beyond the point of getting the kong badges.