You know, I've thought about this problem myself. With so many different image hosting sites, people with personal web pages, etc... its almost impossible to keep track. The knee-jerk reaction has always been "use bookmarks," but if one were to bookmark every notable MOC out there, it would defeat the purpose of having bookmarks due to the tremendous numbers involved.
Personally, I think a Wiki-type solution would be best (although it shouldn't necessarily be editable by anyone). Basically, each ship/vehicle in the Star Wars universe would have it's own page, although pages would be created as needs arise rather than having them all created ahead of time. This has the effect of limiting the MOCs to those based of "real" ships within the universe. While, non-"real" MOCs have there place, it wouldn't really fit the site. On each page, there would be a list of MOCs about the given vehicle and divided by scale (MINI, system, UCS, other). Each list item would consist of a thumbnail, a brief description (if needed), and the MOCer's name/username. Each list item would link to a page with a single large picture (preferrably a 3/4 angle shot), Instructions (which should all be converted to PDF format), and ldraw files.
Of course, the natural question of rights/permissions is bound to come up. Before a MOC can be posted, the creator must must consent and agree to a GPL-like agreement (adapted for LEGO). For those unfamiliar with this, it is an agreement commonly used by open-source software creators which give others the rights to use, modify, and re-distribute the source code. In LEGO terms, this would mean that the MOC creator is releasing the MOC (pictures and/or instructions) for others to use, modify, and re-distribute.
This means that for older MOCs, one would have to contact the original creator of the MOC and get permission. Of course, MOCer's could also volunteer their work. I think initially, it would be a lot of work since only a few people would know and care about it. However, I think after a while it would grow in size and popularity and hopefully get to the point where we would no longer need to hassle others about submitting their MOCs.
The beauty of a LEGO MOC is not the elements that go into it, but the way those elements are put together.