Thanks Martin! I looked but hadn't found that page, must have been using the wrong search keywords.
I think my proposed system fits OK with the 'Logging 2' thing - i.e. it's an incremental step in that direction that can be implemented without hurting anything. Basically my proposal is the 'MUC-like plugins to interface between our logging calls and log backends' part of that page. It also fits in with the default (database logging) given on that page.