Oh, I didn't realize that's why you wanted to do that.  You can't even find xlrd 0.6 on PyPI anymore (or at least I can't find it). But I guess that's what on Debian stable :-/. We'd have to discuss supporting xlrd 0.6 (because it'd also need to be a dep for one of the builds).

I would be -1 on different minimum versions for different parts of tests. Others? @jreback @cpcloud ?