I think Diamond supports USB host.

[qllaoda]

I saw this picture in the service manual:
http://forum.xda-developers.com/attachment.php?attachmentid=235850&stc=1&d=1255155290
In this picture,we can see it is using an USB card reader.So I am sure Diamond supports USB host.At leaset ,the hardware supports.
But we can also see an AC adapter, so maybe Diamond can not power the connected USB devices.
If an external AC adapter is connected , maybe it really supports some USB devices.But if an external AC adapter is needed, it is not very useful.

[Rudegar]

yes there have been several posts about the same thing in the forums
and nobody ever been able to get host outside of the bootloader

and even the ppc devices which do support usbHost require external power
usb is 5volt 0.5amps and
watt == volt * amps
so that mean it would have to be able to supply 2.5Watt out of the usb port
and thats more then most handheld devices can manage