I've never seen any of Shoin's teachings translated into English. However, there is one Essay that was highly influential at this time that was translated. It's called New Theses (Shinron) and was translated by Bob Wakabayashi.
The author Seishisai Aizawa was a samurai from Mito. He wrote Shinron in 1825 and it's basically a blue print for Japan's foreign policy for the next 100+ years. It's amazing to read how many of his suugestions became policy. A truly insightful read.