Plenty of people.
Alex Lowe was on the cover of either Climbing or Rock & Ice doing it, back in the 90s.
An Australian Antarctic cruise company Auroroa Expeditions often takes people on short climbs on shore and sometimes they take people on the easier-angled bergs floating around. Plenty of climbers on yacht trips to the area have done it just playing around between other climbs. Obviously it's dangerous as the bergs can roll over unexpectedly. And you need a wooden board in the Zodiac to stand on, wearing your crampons, as you step off onto the berg.