Here you go (please excuse half-painted miniatures and poor photos!).
The "warg" riders are too small for their legs to work with Oathmark goblins. I couldn't find my Oathmark orcs for a photo, so I've used GW and Ral Partha orcs for comparisons.
The hyena-things are big enough to use in 28mm games, but I think they'd look a bit odd with bigger riders. I was planning to use them as the mounts of a tribe of very small goblins in 28mm and of ogre-types in 15mm. They're a bit bigger than Ral Partha wolves - but those have very small riders.
If I can remember where I've put my Oathmark orcs, I'll post a comparison this evening.
Hope that helps!