Yes, the 'normal' (X11 for desktops) Linux UI for Skype is in Qt. But, have you ever seen that UI on Maemo? Guess not ...
On Maemo, Skype support is in: -telepathy -address book -accounts
So, if N900...
I haven't looked in detail at what Harmattan ships, but even if it ships telepathy-qt, there would likely be some porting work from telepathy-glib to telepathy-qt. I have no idea whether the APIs/plugins for addressbook and accounts are similar or totally different.