When Macallan (now officially Windows CE 5.0) was announced, most people (us included) were expecting to be waiting for the long haul to longhorn - the successor to Windows XP - before it's Release To Manufacturing (RTM). More recently the idea that CE 5 would be a complementary release has become quite widely adopted.
However it would seem that this is now completely inaccurate. Microsoft have announced a technology preview for OEMs and Mobile Device developers, stating at the end of the introduction "Look for the final release in summer 2004!".

Now that we have to eat humble pie on when we would see CE 5, we may not have been completely wrong. In a fact of irony, and Microsoft being a comply that feed of coincidences. Should Longhorn finally arrive sometime late in 2006 as is currently slated. We may also see a Windows CE 6.0 appear at the same time.
Windows Longhorn will in actual fact be Windows NT 6.0. Meaning that the version numbers will be in sync.

Could this have been the plan all along? Only time will tell.
Suffice it to say, we'll bring you all the latest on Windows CE 5 (and 6) as we get it.