I found these jetbike conversions.
My spanish stretches to cerzeva and perhaps cuidad imperiale, so I can't tell you any more, but they certainly look the part.
And these bad boys make me want to buy even more Wraith Lords. You can have too many Wraith Lords, as it implies that all of your exarchs are dead. But a couple more, if they are posed like these, would be a fine addition:
This is just brilliant:
As is this: Proof that investment in plasticard is worthwhile.
And these ideas from Warpstoneflux are brilliant.