Niels, if you like the "Micport Pro 2" in general, why would you not use its headphone output as an aux output? The voltage and impedance levels should be OK, and the manual specifically says that this can be done.
Let me mention one other option for a recorder, but only to rule it out: The Tascam DR-10X. It's extremely small and lightweight and has an XLR-3F input. But it has no phantom powering, and its mike preamp is noisy. At its least sensitive input setting (basically line level), it seems to switch into a different circuit configuration in which it has a very usable signal-to-noise ratio. But then you'd need a preamp with phantom powering in order to drive it! I've used it with the Sound Devices MP-1 and it has worked nicely, but it is a bit of a "solution looking for a problem".
--best regards