[рони]

Вариант ...

var O = {
	"БПИ": {
		"30": {
			"12": [ "2,5" ],
			"24": [ "1,25" ],
			"48": [ "0,65" ]
		},
		"60": {
			"12": [ "5,0" ],
			"24": [ "2,5" ],
			"36": [ "1,5" ],
			"48": [ "1,25" ]
		},
		"125": {
			"12": [ "10" ],
			"24": [ "5" ],
			"48": [ "2,5" ]
		},
		"250": {
			"12": [ "20,0" ],
			"24": [ "10,0" ],
			"48": [ "5,0" ]
		}
	}
};
function look(h) {
    var b = [];
    return function (f, a) {
        var c, a = a || 0, d;
        !b[a] && (b[a] = []);
        for (d in f) if (b[a].push(d) && (c = f[d])&& typeof c=='object') {
            var g = {}, e;
            for (e in c) g[e] = c[e];
            arguments.callee(g, a + 1)
        }
        return b
    }(h)
};
var s=look(O).join('\n');
alert(s);