I have a Kona Dew with the Kona Riser bars, which I assume are similar to those on your Caldera. I had been thinking trekking bars as well, but yesterday put on some Ergon GX2 grips. The bar-ends provide another nice hand position, and so far I love them. I know you asked for opinions on new handlebars, and this may not be what you were asking, but I thought I would throw it out there anyway.