Capitalize your I's, buddy
I think the Dark Eldar hoverboards would be to scale, but would look too gnarly. They're covered with spikes and blades and such, and won't fit with the more refined Eldar aesthetic. Also, the warlock models aren't very dynamic, and you'd have a hard time getting them to fit on the hoverboards. The boards are metal too so it would be a bit of a pinning project. In short, it could look okay, but the amount of effort involved may not be worth it.