Yes you can, just append
:i386 to the download command, like this:
sudo apt-get download <package>:i386
So for you:
sudo apt-get download vlc:i386
I am unaware of any way of automatically downloading a packages dependencies, besides
build-dep but that won't work in your case.
After poking in the manpage a bit more, I have found that you can, in fact, use
build-dep to an extent like this:
sudo apt-get build-dep --download-only vlc:i386
Which will then download the required packages into the current directory. Note however, that
build-dep is looking at compiling the package from source, not installing it from a
.deb so it will suggest things like
gcc which may be needed to compile vlc, but not necessarily install from a
It may be easier to list vlc's main dependencies with
apt-cache depends vlc:i386
If you want to filter by just depends use:
apt-cache depends vlc:i386 | grep 'Depends'
Note that some packages, like
libc6 come by default in Ubuntu, so you won't need to download those. If you just want to download all the dependencies and deal with whether you need them or not later you can use this script:
for i in $(apt-cache depends vlc:i386 | grep -E 'Depends|Recommends|Suggests' | cut -d ':' -f 2,3 | sed -e s/'<'/''/ -e s/'>'/''/); do sudo apt-get download $i 2>>no32.txt; done
This will download all the dependent, recommended, and suggested packages and reroute any errors to
no32.txt. You should take a look in there when you're done, because some needed packages that don't have i386 versions (i.e. they aren't binaries) will be in there.
apt-get download those.
Note that this script isn't very smart, it doesn't take a lot of things into account, so you may get some silly errors, it should work in general however.