After looking and looking for some alternate models (GW wants $20 a pop for these guys) I settled on making up some Daemonette/Spider Centaur models. Wildeyedjester was actually thinking about doing this for a Fantasy Daemon army - but I beat him to the punch!
Just looking at the individual model you would think these would make better Seekers than Fiends. I thought so too. I was quite torn over using them as Fiends because of the size. The regular Fiend model is pretty tall and these guys hug the ground.
I decided to get around this by modeling some taller bases so these guys are up off the ground a bit. By using a round 40mm base instead of the cavalry base I think I have avoided any kind of mix up where people would confuse these for Seekers instead of Fiends.