QMAX
Not quite the same as a helipad, but yes I have had an engine failure immediately after rotating during an offshore towering-type take-off, so it can happen and has.
During the 1970s Bristow used a verical take-off profile from the Wessex for use when taking off from helipads in the jungle/swamps. It had the advantage of getting you back on to a known safe area i.e. the solid wooden/concrete helipad from which you had just departed. I seem to remember that the procedure was to climb vertically to 200 feet and CDP was at the point of rotation. Provided you used a lateral reference for the (slow) descent the only problem was usually in the mind of the pilot involved, as before actually carrying out the procedure it seemed as if it might be a bit hairy. The Wessex had much worse downward visibility than most modern helicopters, so I guess that once the procedure has been practised a few times it may not seem as bad as it looks from just reading about it in the FM.