In 1/400 scale, there is also the German torpedo boat/destroyer "V-108"
produced by Mirage, and the Imperial Russian cruiser "Aurora" and
pre-dreadnought battleship "Potemkin", both of which were originally
moulded by Heller and have since ended up with various Russian and
Eastern European manufacturers, most recently Maquette.
I think Mirage's "Mazur" (Polish gunnery training ship, the first ship
to be sunk in WW2) was originally a WW1 destroyer or torpedo boat, but
I can't remember its exact history.
The late 19th-century pre-dreadnought USS Oregon, represented by the
Glencoe/ITC 1/225 kit, also served in WW1, in fact I think the Glencoe
kit includes colour profiles for the WW1 ship, though I'm not sure if
the kit's armament configuration is correct for WW1.
Finally, Glencoe produced a kit of a WW1 USN 110' submarine chaser in
about 1/72 scale. These vessels also served in WW2, but the kit
definitely represents a WW1 sub chaser.
WW1 and mid/late 19th century ships are a particular interest of mine.
I'm thinking of scratchbuilding a WW1 destroyer or large torpedo boat
in 1/200 or 1/96 scale in the fairly near future. My current
scratchbuild is the turreted monitor/coastal defence ship HMVS
Cerberus, in 1/96 scale, scaled up from the free plans available at
http://www.papershipwright.freeserve.co.uk. This actually
served in WW1 as a submarine depot ship, though I am building it in its
1880s configuration.