Here's a patch which adds support for controlling the maxlevels on command line. Currently, compileall uses a binary choice, either we don't process subdirectories or we process at most 10 subdirectories. This seems to be the case since its inception, in 
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Changeset:
1828 (b464e1d0b2fb) New way of generating .pyc files, thanks to Sjoerd.
User:
Guido van Rossum <guido@python.org>
Date:
1994-08-29 10:52:58 +0000 (1994-08-29)
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The patch adds a new command option, -r, where `-r 0` is equivalent to specifying -l. I guess we can't modify -l to actually control the maxlevels, due to backward compatibility concerns.