There isn't. On the getstart you can actually catch the ctcp event and code off that. But for the send start you need to code stuff after the dcc send command is issued. Which isn't always possible. Yeah, I would love to see this...
Well the whole idea is to have an event that triggers when they actually acccept the send.The problem doing code off the ctcp dcc send and /dcc send is that there is no way of telling if the other user accepted the send or just ignored it.