>>3574
Assuming you're not trolling, getting IIIa level protection on a floor-length robe would be as simple as making it out of layers of a para/aramid like Kevlar and backing it with something stiff, like chainmail or "scale" style thin plates.
That would be ridiculously heavy, though, and out of the question if you want III/III+ or IV protection. There's a reason body armor just armors the center mass vital zone. Fragsuits are just a couple layers of standard body armor with a body suit of nomex and kevlar, which will stop shrapnel and weak pistol bullets but nothing else.
So, if I'm reading into your question right, the only way to turn yourself into a walking tank is to Fred Flintstone an actual tank. You're just not going to get rifle or even reliable pistol proof armor head-to-toe, before you need a motor and wheels to move it.