Princes and Barons definitely can. That's why I thought it was odd that Void Dreamers couldn't.
Maybe they thought better about the idea of having a psyker piloting a jetbike while casting complex psychic spells that need utmost concentration or daemons will erupt from your brain.
Actually, I've got a rather exciting (for me) conversion planned based on that idea using a certain Harlequin vehicle...
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Check out may pan-Eldar projects
Exodites, Corsairs, Craftworld, True Kin, Croneworld (soon) and one Shadowseer!: http://www.thedarkcity.net/t14405-corsairs-exodites-craftworlders-and-hopefully-kabalites-soon