Custom Bike Rack

Hi there, im thinking of buying or making a removable bike rack for the front of my td,
I have a longish draw bar, made of 50mm box section. I cant buy a bolt-onto-towbar model as my towball is a removable one and hence doesn't have the 2 fixing bolts.
Anyone made one up before? It will be only ever holding 1 bike of 12kg so not bothered about extra nose weight.
Anyone seen one?, or any ideas for the best way to attach?
Maybe a bracket which sits over the draw bar and bolts on?
I have a longish draw bar, made of 50mm box section. I cant buy a bolt-onto-towbar model as my towball is a removable one and hence doesn't have the 2 fixing bolts.
Anyone made one up before? It will be only ever holding 1 bike of 12kg so not bothered about extra nose weight.
Anyone seen one?, or any ideas for the best way to attach?
Maybe a bracket which sits over the draw bar and bolts on?