I would love to build a new trail, especially one thats more MTB specific. The Cleveland National Forest doesn't have any user specific trails they are all multi use. I would like to build a nice flow trail with some tech, like beginner to intermediate. In order to to even get the new ranger to consider a new trail it would take a lot of effort from the mountain bike community. One voice cannot change their thinking but if we all start reaching out in numbers and they start seeing more involvement from the community they might become more open to the idea. From talking to different people within the FS community many believe that the trails they have already are deteriorated, and they make comments like " No new trails can be built till the trails we have are all fixed, we have too much to take care of already". Once their one way mind set has been changed then it would require the usual GPS mapping, Submitting a request to the National Environmental Protection Agency (NEPA) for approval, then they would most likely send an FS engineer to check for sustainable soil and run off layout. It would be very involved and would most likely cost lots of money, which i don't think they have.
On the other hand, non established trails don't take any funding, because they are not really legit. Such as the luge, and since the luge used to be a road they turn a blind eye. I believe right now they are in the process of legalizing the luge and buying land at the beginning of STT starts on. so as far as i know only old service roads and trails can become re-established single track. Off of STT there are a few over grown roads that could be converted back to single track but the problem is they end up in private property. So yes there are possibilities of using these old roads but we would need to get the land owners consent to build an exit. I have no idea who owns the land or how to contact so its kind of a good luck.