You could mention "hg out" where you talk about pushing all the changes.

About hg graft, I would assume that most of the patches grafted from 3.x don't work right away on 2.7, or if the graft work the code might still need to be changed.  How do you deal with this situation?  Is there a --no-commit option for graft?  (I haven't used graft yet)

> Re first committing to 2.7 then 3.2 and then merge

FWIW now that 2.7 is "getting old" I agree that committing on 3.x first and possibly backporting to 2.7 later is more common.

> Any other comments?

[Disclaimer: This is not directly related to your patch but about other things mentioned in the same page. Here I'm describing my workflow, it might or might not be better than the one suggested by the devguide, but if it is feel free to include the relevant bits in the patch]
That page suggest to push from e.g. 3.2 to py3k.  I usually do the opposite, i.e. I always pull the 3.2 changes in py3k.  I guess it's just a matter of preferences, but iiuc if you push and there's a conflict the push will fail, whereas the pull will usually work better.  Not using push myself I can't tell how often that happens and if that's a problem at all.
I also have all the clones configured to pull and push from h.p.o.  As soon as I "enter" a clone I "hg pull -u" the changes from h.p.o, and if I have to pull some local changesets too I also "hg pull -u ../py3.2".  When I'm done I "hg push" from py3k (or sometimes from 2.7, if the changes don't apply to 3.x).  I also "hg pull -u" just before committing, in case someone pushed something in the meanwhile.
This means that:
 * I don't have to chain-pulling following 2.7<-3.2<-default, and thus I don't need the "simple script" suggested by the devguide;
 * If I have uncommitted changes in one of the clone, I can deal with them one by one, and not when I run some scripts that tries to update everything at once;
 * I download the same changes from h.p.o 2-3 times;
 * I have to do a bit more typing;

This can be summarized with:
$ cd py32
$ hg pull -u
$ hg import --no-c patch.diff
$ # review, run tests, etc.
$ hg ci -m '...'
$ cd ../py3k
$ hg pull -u
$ hg pull -u ../3.2
$ hg merge 3.2
$ # solve conflicts, run tests, etc.
$ hg ci -m '...'
$ hg push