just got to figure out which .deb file the wanted binary lives in...

Here's what I do:

1. Go to http://www.debian.org/distrib/packages
2. At the bottom of the page is the search window.
3. Type your binary name (e.g. 'date') into the "Search the contents" window.
4. Hit "Search". The results come back.
5. Top of the list, in this case, is bin/date, in base/shellutils

Now, if you click on the "base/shellutils" link, it'll take you to a page summarising dependencies, etc. Take a look at it. However, from here, it'll probably take you to x86 binaries. We want ARM binaries, so...

6. Go to http://http.us.debian.org/debian/dists/stable/main/binary-arm/
7. Click on (in this example) "base"
8. Grab the "shellutils_version.deb" file.

This is the .deb file containing the binary files we wanted (and probably more besides).

Now, to unpack the file, you'll either need a copy of 'ar' on your player, or a Linux/Cygwin installation handy:

1. ar p file.deb data.tar.gz > file.tar.gz
2. Send this file to the empeg (either using Hijack or ZModem). I generally put the .tar.gz files into /drive0, so that they're not overwritten by an upgrade.
3. Unpack it into the root.

Presto, a copy of date for your empeg.