I have noticed two things:
(1) end-users have lots of headaches configuring /etc/apt/sources.list
(2) in general, releasing your own binaries doesn't work too well,
because:
	* you often have to download other packages.  "dependency hell"
	* there is no security

So, I think apt should be involved in (2), and (1) should be
fixed.

Here's how:
* there should be a directory, possibly called /etc/apt/sources.d
* multiple sources.lists should be permitted in this directory
* then, mirrors can give mirror files, that users can download and
stick in their /etc/apt/sources.d (This process could be automated
with a nice GUI via mime-types/handlers!)
* developers can make their own binaries, and refer to other
packages for dependencies
* apt supports signing.  Developers can sign their packages.
* perhaps trust metrics could be used to decide whether to trust
an entities' packages.  Anyway, this is a separate issue.

So, the plan is:
* add support for /etc/apt/sources.d in APT
* add a program that handles .apt files, or whatever, with a nice
friendly GUI (asks for root passwd, etc. to install .apt files),
 and make it a default handler for .apt files