Note that this is not possible, for a very simple reason: resolving the label changes the line breaking and page breaking, which can change the labels. The problem is that -- in some sense -- TeX is too powerful: Even the slightest change in the document can change the way how the whole rest of the document is processed by the program, and that's not only on the "where will the stuff go" layer, but also "how will my macros be defined" layer.
As an example, consider that you can have different section headers on even and odd page. This basically means that you have two internal macros --
\sectioneven -- for the section, and you call the correct one depending on the parity of the page number. First, this itself is a two-compilation thing: you have to remember the page number from the previous compilation to get it right. Second, the user can define
\sectioneven in a very strange way, he can decide that one of them will change the basic macros of the engine etc. and since you can't predict this, you can't know for sure what's going on until you trully process the document with everything that should be there.
Needless to say, as noted above, custom formats do exist and they can be formed moreorless of what you put in the preamble. More details are for instance in Own cls to fmt conversion.