Different font sizes in the same annotation of matplotlib

I need to annotate a pylab rectangle with few data lines - which are of different length. Searching through the matplotlib documentation, and Googling, I could not find a way to give different parts of an annotation different sizes.

The following snippet demonstrates the problem:

import pylab
from matplotlib.patches import Rectangle
pylab.rcParams['verbose.level'] = 'debug-annoying' 

def draw_rectangle(lower, upper, entry):
    ax = pylab.subplot(111)
    r = Rectangle( lower, upper[0]-lower[0], upper[1] - lower[1],
            edgecolor='k')
    ax.add_patch(r)

    textRank = str(entry['rank'])
    textTeamName = entry['teamName']
    textSubmissionDate = entry['submissionDate']
    text = textRank + "\n" + textTeamName + "\n" + textSubmissionDate

    ax.add_artist(r)
    rx, ry = r.get_xy()
    cx = rx + r.get_width()/2.0
    cy = ry + r.get_height()/2.0

    ax.annotate(text, (cx, cy), color='w', weight='bold', ha='center', va='center', size=14)

if __name__ == '__main__':
    entry = {'rank': 22, 'submissionDate': '12/21/2012 4:58:45 AM', 'teamName': 'A very very very very very very very very very very long name'}
    lower = [0,0]
    upper = [1,1]
    draw_rectangle(lower, upper, entry)
    pylab.show()

E.g., is there a way to have the annotation where the font size of 'teamName' is different than the font size of 'rank'?

Another problem is I could not find a way for the font size to correlate to the zooming:

I'm creating a treemap plot, namely, the pylab window is filled with different sized rectangles. If I want to create annotations for the different rectangles, the long data need to be of very small size (to stay within the respective rectangles' boundaries). H