An idle thought - could stimulants, specifically dopamine reuptake inhibitors (like Ritalin, Adderall, Vyvanse) treat the symptoms of RLS? Intuitively I would think yes, given that dopamine agonists are widely used for RLS.
Presumably the reason this isn't done is that they're wakefulness-promoting, and most people experience RLS at night...? (I experience it primarily during the day and it abates at night, so am unusual in that regard.)