Christian wrote:
I guess what makes these sentences
grammatical is that "go home, sit down and play" can be seen
as a single (if complex) transitive verb.  So can "buy and
devour".  "Buy and come home" doesn't work well as a unitary
predicate, because its component actions don't make coherent

I agree with you, though I think others have analyzed it
differently (I don't know how).  The problem with this kind of
explanation (for syntax, anyway) is that there's no way to
predictably say what can work as one of these complex
transitive verbs and what can't.  Also, the actual syntactic
structure is problematic.

Christian continues:
The fact that "come home" is intransitive isn't the
problem, as can be evidenced by the following sentence, which
sounds sound to me:

"Venice is one of those cities you want to see and die."

The reason I said the problem is with the intransitive is that in
the productive version of relativization (well, more productive,
anyway.  Actually, I don't even know if it's more productive...),
there are some things you can't do:

a. I saw a cake and devoured it.
a'. The cake I saw and devoured.
b. I saw a man and exited.
b'. *The man I saw and exited.

In conjunction, you can relativize an object that's the object of
both verbs and corresponds to two identical gaps in the
relative clause.  You can't do it when the first conjoined verb
is transitive and the second is intransitive.  Also, the two verbs
don't have to have anything to do with each other, the way
they seem to in the (there's got to be a name for this construction)
construction I presented yesterday.

So while I agree with your assessment--that the whole thing
is, essentially, just one big transitive verb--I was looking for the
reason that you can use intransitives verb along with transitive
verbs in this way.  The first answer is it has something to do
with background information.  In that case, maybe it's akin to
a verb in a polysynthetic language, where everything that's
relevant is packed into the verb (!).  It does seem like you can
just build them up at will:

"The cake I went to the store, saw, wanted, bought, went home,
sliced up, invited my friends over, and devoured."

Oh, an interesting one.  What do people think about this

c. I went to the store and saw a cake.
c'. The cake I went to the store and saw.
d. I owned a Honda and saw a cake.
d'. *The cake I owned a Honda and saw.

Seems like this type of relativization is sensitive to the "and then"
type of "and" and the "and also" type of and.  It would be better
if I could think up a (d) example that were actually related to
seeing a cake, but, well, it's early.

"sunly eleSkarez ygralleryf ydZZixelje je ox2mejze."
"No eternal reward will forgive us now for wasting the dawn."

-Jim Morrison