Johan (SM6LKM) has a nice and simple DDS board which looks perfect for this job, and -much to my surprise- the AD9832 is easily available in this country, about 10 Euro's per chip. Unfortunately, the AD9832 is only available in SMD TSSOP(!) case which is not very "veroboard-friendly".
A first attempt to make a home-etched PCB failed because the copper strips are too thin (and my printer too bad). Making a few cuts into the copper with a knife may be a better solution, I will try this in the short xmas vacation.