IMHO, the motherboard section in the wiki is a great idea, but ultimately futile. As mentioned above, MBs change too often and people don't update the wiki (myself included). When I was looking for a MB I started with the wiki, and basically none of the entries were available any longer. Ultimately I based my choice on manufacturer, features, and chipset. I don't remember the exact MB I bought, but I doubt the exact version is still available and that's the real problem.
A couple ideas that MAY help. As mentioned above, change it from motherboard to chipset info, this is what most of us talk in anyway. For example, if someone asked what a good MB is for integrated graphics, the typical response isn't to suggest a MB, but to suggest getting one with an nvidia 6150 chipset or whatever.
Another idea, instead of asking people to create a generic wiki page entry have a "submit your hardware" button that asks a series of questions or opens a template. The template can have a number canned items such as integrated graphics chipset, manufacturer, number of pci slots, success/failure details, version of LMCE tested with, other notes, etc. etc. etc. Clicking submit then creates a uniform wiki entry or even an entry in a searchable database. Yes, I'm sure creating wiki pages is easy stuff, but in the end people are just not doing it. Making it dead simple and not requiring a login for wiki entry or somehow using logins from this forum would probably increase the amount of user supplied info on the wiki.