Hi Don't know if you have found anything yet but how about a sailing trip on Lake Malawi theres a company called Danforth Yachting that do sailing trips, the lake is full of colourful fish, you could spend nights on private islands or sail up the Shire River looking out for hippos and elephants and then go on a safari in Liwonde Nation Park which the river goes through. There are beautiful beach all around the lake.