The Android emulator is based on QEMU. Even if the emulator version is so ancient, there appears to be support for passing USB devices from the host. It does not seem to be available for ARM devices though, the emulated ARM machine does not have a USB controller. (I have already tried enabling all USB host controllers for the goldfish_armv7 kernel based on Linux 3.4, without luck. The default emulator goldfish_armv7 kernel does not even have Host USB enabled.)
If you are not limited to ARM and can use x86, then I suggest to check out http://www.android-x86.org/, its images can be used with a standard QEMU i386 (or x86_64) machine. This also yields better performance by using the KVM extension on Linux.
To passthrough a USB device with of vendor ID 1234 and device ID abcd, you can run the emulator command:
emulator -avd x86-machine -qemu -usb -usbdevice host:1234:abcd
Or, when using QEMU:
qemu-system-i386 -m 1G -cdrom android-x86.iso -usb -usbdevice host:1234:abcd
You will need read/write permissions for /dev/bus/usb/XXX/YYY, for that you can create a udev rule such as:
SUBSYSTEM!="usb", GOTO="end_skip_usb"
ATTRS{idVendor}=="1234", ATTRS{idProduct}=="abcd", TAG+="uaccess"
LABEL="end_skip_usb"
Now, upon insertion of the USB device, your emulator should recognize a USB device. This is tested for a Linux installation with a Android x86 4.3 image.