I got my n810 a few days ago and from a first glance at the usb port i don't think it's an anomaly. At least my machine seems to have a recepticle that will also accept a micro-a plug. This means that the recepticle is usb otg compliant and will allow you to automatically switch into host mode by just using a micro-a equipped cable. There's no magic involved then, Nokia just did it right.

I just ordered the required cable myself to verify this.