RFC 4253 says of SSH:
6.1. Maximum Packet Length
All implementations MUST be able to process packets with an uncompressed payload length of 32768 bytes or less and a total packet size of 35000 bytes or less (including 'packet_length', 'padding_length', 'payload', 'random padding', and 'mac'). The maximum of 35000 bytes is an arbitrarily chosen value that is larger than the uncompressed length noted above. Implementations SHOULD support longer packets, where they might be needed. For example, if an implementation wants to send a very large number of certificates, the larger packets MAY be sent if the identification string indicates that the other party is able to process them. However, implementations SHOULD check that the packet length is reasonable in order for the implementation to avoid denial of service and/or buffer overflow attacks.
It does not say what the maximum packet length should be but it does advise that the length should be 'reasonable'.
Cisco implementations have a 35000 bytes maximum packet length; anything larger is dropped.
I tried googling for a similar setting in OpenSSH but came out empty.
Does OpenSSH have such a limit?