I've got baskets mounted on at least 4 bikes currently (including my Sam) with basket-capable racks on a couple others. And I have a very strong personal aesthetic dislike of any front racks that attach to the fork dropouts, as well as racks or bikes that require P-Clamps (so ugly!)
I know (I think?) that it's not recommended, but I have no issue with running a Wald 137 mounted on either a Marks Rack (my Sam) or a Nitto M-18 (two other bikes).
I had a couple bikes with the cheapo ($15) Sunlight front rack that mounts to the Canti bolts and fork crown, including one running a Wald 139, but I had to use a strap to connect the front of the basket to the stem to take some of the weight, which is less than ideal and the rack will eventually fail anyway. But for the price of one Nitto front rack, you can blow through several of these and still be money ahead ;-)
I also really like the Velo Orange Flat-Pack rack, which is rock solid and has a wider platform than the small Nitto racks. I didn't try it with a 139, but I'm confident it would work fine. I also have two bikes running Jack-The-Bike-Racks and love those racks - they make great, solid basket platforms.
Mike M