One of the widely celebrated (yet controversial) Seon masters of recent Korean history, Kyeong Heo has an interesting tale regarding this. It so happened that his own discple had attained greater siddhis that himself, and so his disciple Man Gong attracted a constant stream of visitors, asking about such things as missing livestock and the like. One day, a novice at the temple went missing, and Kyeong Heo desperately searched for him. Failing to find him, he resorted to asking Man Gong who used his siddhis to find the novice. However, there came a point where Man Gong's constant display of siddhis raised potential problems, so Kyeong Heo asked Man Gong to never do so again, advice which Man Gong followed even at the expense of his own comfort.
More recently, the great grandmother of the great modern Korean master Il Ta displayed such miracles that the entire family of 41 people ordained. The great grandmother in her old age took up the advice of a passing monk to practice the recitation of the Buddha's name single mindedly. This she did, and after several years she attained siddhis as a laywoman. She predicted all kinds of events and prevented several calamities, such as a fire right next to the cotton processing plant of her sons. Eventually, the family became concerned with her displays and requested another master to advise on the situation, after which she no longer showed her siddhis. Upon her passing, her body emitted such powerful light for several days that the townspeople thought a fire was burning down the house. Having witnessed such a miracle, the 41 family members and several slaves ordained among whom Master Il Ta became the most accomplished and renowned.
Furtherback in Korean history, the master Jin Mook was renowned for performing all kinds of miracles. He is said to have come across fishers by a riverbed, and failing to convince them of cause and effect through words, he asked to have some of their fish soup. Having had the soup, he promptly defecated living fish into the river, thereby converting the fishermen.
Also, some interesting relics of a Chinese master: http://slz.goodweb.cn/monk_22.asp
That website features the relics of many, many Chinese practitioners, both lay and ordained.