Rumours of the Nokia N93 emerged last Novemeber shortly after the release of the Nokia N92.
It was something of a suprise when Nokia did not announce a S60 3rd Edition version / sucessor to the sucessful Nokia N70 at 3GSM. The rumoured N73 (also called the N72) looks to fill this gap. It will likely see a bump in specifications. Two devices families in the N70 form factor are likely, one with WiFi and one without.
It is importat to realise that rumoured devices may never be announced; many protpypes are developed, and some will be stopped at one of the many stages of development between the drawing board and the production line. It is also worth noting that device names are subject to change and are usually not decided until quite late on in the development cycle.
There has now been an almost 5 month gap since the last new S60 device was announced at the NMC in November 2005, which is one of the longest gaps in recent years between announcements of high end Nokia phones. It is likely that part of the reason for this gap is a desire from Nokia to start shipping S60 3rd Edition devices before announcing new ones. There are currently 8 S60 3rd Edition devices about to ship or that have just started shipping (E60, E61, E70, N91, N92, N80, N71, 3250). We can expect announcement of S60 devices in both the Nseries, Eseries and standard Nokia phones in the not too distant future.