Keep in mind what would be required to have something that was even the most pale imitation of what deviantART does.
It would require enough drive space for a boatload of .rmskin files and preview images.
It would require enough processing power to support the searches, and enough bandwidth to support all the downloading.
It would need to require a login, or it would be entirely full of spam and ads for porno and Viagra within hours. Literally hours.
This means it would require a method, and one or more people, to manage these accounts, see porno and Viagra above.
It would require software that would allow organization and searching by at least "name", "category", "author", "date", "popularity". Probably others.
It would need to allow "submissions" to be created, edited and deleted. A submission is a combination of the file, one or more preview images, and a pretty robust description.
It would need to allow "comments" to be created, edited and deleted on the submission by other users. Code boxes, images, quoting, text formatting, all the same kind of things you see in the forum would be needed.
It would require one or more people to check and validate all submissions, and moderate comments. See porno and Viagra above.
It would need to gather and track statistics about how many times things are viewed and downloaded.
It would require both software tools, and actual people, to monitor, maintain and manage things. Customize.org is a perfect example of how quickly it can all go wrong if it is not carefully managed. It's a lot more work than you might think just to keep these forums from spinning out of control.