JoostinOnline has released CheckRegion for the Wii, which gives various pieces of information on the device, such as serial number and serial code, here is a quote from the source:
CheckRegion gives region related information about your Wii. This includes your model, serial number, serial code, and country code. It’s main purpose is a library for use in other applications such as NEEK2O and SysCheck, but it includes a sample program which reports all the information.
All you need is a way to run the dol. Any exploit or app/channel capable of loading dol files should work. No cIOS is needed.