well... the reason we DONT have custom skins (besides the new, slight modded ones) is because they are not our forums to mess with. and with as many people as we get here each day, it would REALLY lag up the server. Instead of sending just the table and database files, it would also have to send the images over and over. more than 10,000 people a day request this page... think how bad that would lag it up. So the problem here is money. If we had a fast enough server, which a t3 connection, im sure we could customise the forums more than we have been. but other than that, i dont see it coming any time soon.
One thought i have, to lower the load on the server, would be to have specific image servers for each skin set. their primary function would be the images, and possible all those old threads that hardly anyone ever looks at. but that would also cost alot of money, something which BF does not have since we are a free gaming forum.