Rhino/Python script the randomly jitters mesh vertices along their normals, scaled by the face size.

MeshJitter.py

import rhinoscriptsyntax as rs
import math, random

obj = rs.GetObject("Select mesh", rs.filter.mesh, True)
sigma = rs.GetReal("Gaussian sigma", .1)
vertices = rs.MeshVertices(obj)
faces = rs.MeshFaceVertices(obj)
normals = rs.MeshVertexNormals(obj)
if vertices and faces:
    modified = []
    for i in range(len(vertices)):
        vertex = vertices[i]
        normal = normals[i]
        face = faces[rs.MeshVertexFaces(obj, i)[0]]
        a = vertices[face[0]]
        b = vertices[face[1]]
        dist = rs.Distance(a, b)
        amt = dist * math.fabs(random.gauss(0, sigma))
        vertex = (
            vertex[0] + amt * normal[0],
            vertex[1] + amt * normal[1],
            vertex[2] + amt * normal[2])
        modified.append(vertex)
    rs.AddMesh(modified, faces)