Here are some neat, modular insulated panels (Al-EPS Foam-Al sandwich) that come in a variety of colors and overcoated with something that sounds a lot like Valspar's KlearKote (sp?):
https://www.structall.com/catalog/pr...num-snapnlock/
There's even an option of ordering the panels with an integrated extruded beam(s) inside the panel (not an I-Beam, though).
Doesn't look like they offer any curved transition pieces, though.