I would think tiller steering is more suitable for RL28s. A tiller is much more responsive and gives so much better feel than a wheel, and an RL28 is light enough to still be easily controllable with a tiller. And being a light boat it is a safety advantage to be able to respond quickly to a strong gust or wind shift in strong winds.
The only time the tiller gets heavy is when reaching in strong winds and Rob Legg recommends raising the centreboard half way in these conditions to get better balance. And as you have to waggle the tiller as every wave hits the side of the boat, the wheel would get tedious.
Of course you gain a lot of cockpit space with a wheel. But in answer to your question, no, I don't know of any RL28s fitted with a wheel.