I'm not sure if I really tested grounding the ID pin. I only have an N800, and I used the USB OTG (mini-B) host adapter from jolouis (which has the ID pin grounded) along with a mini-B to micro-B adapter. I assumed that would work to conclusively test the N900's hardware USB host capability.

But I later tried the same set-up with a friend's N810 and discovered that it didn't put his N810 into host mode, either.

By the way, transferring files via WiFi to/from the N900 has been pretty quick and painless. The networking speed on the N900 is much improved over the NITs. The most common method I've used for transferring files has been simply attaching the file to an e-mail. That is really quite a painless solution.

As for other devices, I have managed to get my Stowaway BT keyboard to work with the N900. I haven't tried a mouse yet, since I can't find an inexpensive BT mouse ( < $40 ) anywhere.