Objects of Perception
One can think of perception as a relation between states (or acts) and objects, the objects that are perceived. Alternatively, one can think of it a relation between a state and a content, the information acquired or represented in the perception.
Content is something that excludes possibilities. Suppose I have a perception of an elephant standing in front of me. What possibilities are thereby excluded? There are at least two reasonable answers: 1) the exluded possibilities are possibilities where there is no elephant in front of me; 2) the excluded possibilities are possibilities where I do not have that experience. Regarded as sets of possible situations, on the first account, the content of my perception is a set of situations in which there is an elephant in front of me. On the second, it is a set of situations where I have the phenomenal experience I actually have, even if it is caused by evil scientists. (Strictly, "I" need not be me, but can be whatever is in the center of the relevant situation.)
I don't think we have to choose between (1) and (2). Instead, we can say that my experience has both kinds of content. I've also left it open what determines content (1), whether that is, say, certain causal relations between the state and the elephant, or, say, the beliefs typically caused by the state. Maybe one could also multiply contents here, but I suspect most of these contents (like the one determined by causal relations) serve no philosophical purpose.
As a proponent of the state-content view, one shouldn't deny that we perceive objects. Of course we sometimes perceive tables and elephants. Perhaps perceiving an elephant means being in a perceptual state that is caused by an elephant. Presumably the state's (1)-content must also involve an elephant. (Otherwise a halluzination of a mouse caused by an elephant would count as a perception of the elephant.)
An advantage of the state-content view is that it easily handles halluzinations: when I halluzinate the elephant, the contents of my experience can be just the same as when I see the elephant. In this case, there exists no perceived object, and there's no need to introduce special sense-datum objects.
However, the sense-datum objects employed by (some) state-object theories are useful not only to handle halluzinations but also to make sense of a natural way of talking about halluzinations. Halluzinating a red patch, it is natural to say "I see a red patch". Sense-datum patches provide for a simple, literal interpretation of this claim. Other accounts have to say that the claim really only means that I have an experience whose content is like the content of seeing a red patch, or that I'm being appeared to redly, etc.
Now if we have content, we also have parts of content. Those parts can do part of the job of sense-data. Take (1)-content: When I halluzinate a red patch, there presumably is a red patch in front of all my counterparts in the (1)-content of my experience. Consider the trans-world fusion of these patches. It might be taken as the patch I claim see. (It's interesting that the lump theory of ordinary objects can deal much more easily with such cases than the counterpart theory.)
That lumpy patch also exists in cases of veridical perception. One might say that in such cases I see the ordinary, actual patch in virtue of having an experience whose (1)-content involves a trans-world fusion containing the actual patch. (Which is another way of specifying the object of perceptions.) In many respects, the lumpy patch is then like a sense-datum patch: it is an object of halluzinatory experience, it is not located in ordinary, actual space (even though it is extended, and thus somehow located in an extra-ordinary space), and it is the immediate object of perception insofar as ordinary patches are perceived in virtue of 'apprehending' the lumpy patch.
On the other hand, sense-data are meant to constitute the phenomenal character of experiences. The lumpy parts of (1)-content seem ill-suited to that. We would have to use parts of (2)-content, but it's hard to see how that could work.
Then again, if we give up using the lumpy objects as constituting phenomenal character, and instead focus on their use for making sense of ordinary descriptions of halluzinations, there is no reason to restrict the lumpy objects to colour patches. It is natural to say that I halluzinate a pink elephant, and when I do, there presumably is a lumpy pink elephant in the (1)-content of my experience to make literal sense of this.
There are other lumps that might do other parts of the job of sense data. Thus some of my perceptual-phenomenal counterparts -- the members of the (2)-content -- are seeing a real elephant, others are seeing a fake elephant, others are halluzinating an elephant, etc. Suppose we can draw a line between halluzinating and veridical seeing (such that seeing a fake elephant counts as seeing). Then consider the trans-world fusion of all the objects my perceptual-phenomenal counterparts see. This is a lump containing elephants and other things that look like elephants (to the relevant counterpart). One might take this lump as a kind of phenomenal sense-datum.