I have not seen any.
'Abdu'l-Baha did not wish His birthday remembered as it was on the Declaration of the Bab, and Shoghi Effendi did not wish his birthday remembered (WOB, p. 151
), though both of these cases could be interpreted (as per context as well) as being due to their wish for their respective positions not to be overemphasized.
I have seen (sorry, but I cannot find it now to confirm, but I remember noting it at the time for interest in this topic) that a message had been sent by the House of Justice wishing a happy birthday to Dizzy Gillespie (I think it was his 75th birthday--a birthday on which he held a concert which Wikipedia notes he was to have dedicated to the centenary of Baha'u'llah's passing). This might not be an encouragement to commemorate them, but it would seem, at the least, to suggest there nothing being against people holding them.