Hooray! I've found a hub that works! ...but I'm testing like crazy.
1. Gigaware USB 2.0 4-port hub
3. Archos A70H 250gb
This D-link hub
worked just once or twice, then gave up. Very inconsistent. It may be dying, though. I picked up the Gigaware on a whim and am very pleased so far.
I'm using old eFilm card readers like this
(SDHC and CompactFlash) with it. Card sizes 1gb up to 16gb. Both will mount without the hub, but fail to copy filesÔÇöthe LED goes out and the system says "External storage unexpectedly removed."
For host cables, I have two:
DigiKey, mentioned in the adapters thread, and
Cameras (connected directly): Nikon D90 and D200, Canon S90. Transfer is slower than with a card reader. Also, movie files over about 100mb will not transfer; AVI from Nikon, MOV from Canon. They are fine with a card reader/hub and on my Mac (10.7 Lion), so it must be a limitation of Archos or Android.
An old Seagate 500mb external HD (powered) also works.
I bought the A70H to be a photo downloader and media player like my beloved 504, as well as an e-reader and tablet. Pity Archos didn't give the port a little more juice; we should not have to jump through hoops like this! I even tried UrukDroid, but the card readers still didn't work (one keyboard did, that's all). The 504 (with docking adapter) can power hard drives and mount anything.