Coming from a regular *nix distro, it is very tempting to expect the same exact functionality on your *nix phone as well. I know I did.

In the past, however, plenty of people have reported problems after doing -upgrades, so I stay away from it.

HAM is terribly slow to read repo's and such.

After a reflash, I always install FapMan (Faster Application Manager) first. If I need to be upgrading apps I would use FapMan.

Like I said, some people here might be able to help you install hildon desktop without a reflash or other components, But if you hardly have anything on the device anyway, I would opt for the reflash, if only to have a cleann device to start workinng with, that you have installed yourself and know inside out.

That being said: You could try and see what happens if you download the deb for hildon-desktop and see what happens if you throw dpkg -i at it.

http://maemo.org/packages/view/hildon-desktop/