Weapon and cloak is also possible in 3.5 with a cloak that acts as a shield ;p
As a kid, one thing the cloak did was define me in whatever imaginary game we were playing. Without the cloak, I was just some nerdy kid in suburban America. But with the cloak, I was a mighty warrior, or a roguish assassin, or a wizened spell slinger. In some sense, the cloak actually was the character.
So, here's a bizarre mechanic idea: what if the cloak some how "absorbs" some of PCs essence. Every couple of levels, some bit of the character is actually assumed by the cloak rather than the character himself. Maybe a hit point or two, a +1 Ref save or BAB, maybe a couple skill points. Exactly what part of his soul goes 'into' the cloak is a PC decision.
The cloak doesn't really possess these qualities, but, without the cloak, the PC lacks these qualities. The PC is simply not so heroic without his cloak, just as that suburban kid 25 years ago was not so heroic without his cloak.
In general, this makes no difference in play-- except in a few rare moments in which the PC is particularly vulnerable.
Now it's a bad idea to have a mechanic that only weakens the PC, so there needs to something to offset this, especially at crucial moments. So whenever the PC is deprived of his cloak for dramatic reasons-- incinerated by dragon breath, snatched by malevolent fey, hung up on grasping branches in the evil forest-- he can choose to expend a "hero point" (or some similar resource) to get back double the essential points in the cloak enabling him to really shine in his moment of dire need-- and without the need of his "security blanket".
Again thinking back to being a kid, the most dramatic moments were often those when the cloak came off: the monster grabbed the hem, I tripped up, wriggled out of the cloak, then came instantly and plunged my sword into its scaly breast!
Of course, this character "essence battery" doesn't have to be a cloak: a walking stick, a hat, a waistcoat, a weapon, a pair of boots, whatever fits the player's character concept. Furthermore, I'd allow the player to redefine the item at anytime (between adventures, obviously), in order to keep up with the evolution of the character: change the item itself (eg, from cloak to walking stick), and change the nature of the "essence" it contains (eg, move a couple hitpoint back 'into' the PC and transfer +1 will save into the item). It might also be appropriate to have the cloak slowly stop storing this essence as the character levels and gains the "wherewithal" to contain all his heroism himself.
Something like this would probably work best in a low-power setting in which the characters aren't already presumed to be superheroic. It most likely doesn't do well with power-gaming, either; I'm sure there are LOTS of loopholes to exploit using a mechanic like this.