import matplotlib.colorbar as cbar
import pylab as pl
import numpy as np

N = 50
xs = np.random.randint(0, 100, N)
ys = np.random.randint(0, 100, N)
ws = np.random.randint(10, 20, N)
hs = np.random.randint(10, 20, N)
vs = np.random.randn(N)

normal = pl.normalize(vs.min(), vs.max())
colors = pl.cm.jet(normal(vs))

ax = pl.subplot(111)
for x,y,w,h,c in zip(xs,ys,ws,hs,colors):
    rect = pl.Rectangle((x,y),w,h,color=c)
    ax.add_patch(rect)

cax, _ = cbar.make_axes(ax) 
cb2 = cbar.ColorbarBase(cax, cmap=pl.cm.jet,norm=normal) 

ax.set_xlim(0,120)
ax.set_ylim(0,120)
pl.show()