I have an MTB front mech with 9sp 105 STIs on my crosser. To be fair it’s not a very modern MTB mech – it’s a Deore LX, which dates it enough – for those wanting a precise date, it’s marked as an M550. Also designed to work with standard MTB chainrings (ie 46T big ring). However it might be old, but it’s a top swing, with similar looking geometry to modern stuff.
What isn’t mentioned is what chainset you’re using – if you’re using road sized rings as would be normal for a road tourer then you want a road front mech.
As for the original question and most of the responses, the question should surely be “drop bars on MTBers touring bike”. I have standard drops on mine, as do most other people I’ve seen – it’s what comes as standard on bikes sold for touring.