/cgl/ - Cosplay & EGL

Does anyone have ideas on how to go about creating a "hiltless" katana like pic related? I'm assuming the highest quality result would be from shaping a wood plank, but I don't really have access to the tools or workspace to do precise woodworking.

A big problem is that it has to have a gentle curve, so many options based around using a perfectly straight base like a dowel that would give good stability are ruled out since they give unfavorable results.

For example, I've been thinking about using a rigid foam, but I'm afraid the sword I want to make (which is ~5 feet long) would be liable to snap even if I made it in segments that lock together. Otherwise I'd just get an 8x4ft board of insulation foam and cut it out.