For a large brake Upgrade I made some customized brakes for my ke25 (I'm not sure if they use the same struts). Any way if you are pretty handy with a drill, hack saw, file and arc welder you should be able to do something similar. I am using some 88 magna ventilated disks (114.3PCD) on a ke35 hub which is redrilled to the magna PCD. I am also using ke35 bearings. I have then fabricated plates to mount VL finned calipers and welded spacers and nuts on the inside so I can just bolt the calipers on to the plate.
Depending on how creative you are you should be able to fit some very big brakes on a very tight budget. (I got most parts from the wreckers).