When you say "fast action" do you mead a tip action or stiff rod? For me fast means tip action and stiff is a rod which is rated wrong which feels nicer with a heavier line.
For a single hand TFO
BVK 3wt there is a two piece conversion kit handle which makes it a 10ft switch rod but it does not make it stiffer although in this video a 235gr Ambush and a floating tip is cast. I have not tried it with conversion handle but BVK 3wt is very nice single hand rod.