i thought about it a couple of month ago but i wasn't sure if it it's necessary. you can always post a pm on forum, create a topic and if anyone would be interested - he will simply answer. of course we could try to create a paralel messaging system and signups for just traing duels.
Of course you can post on here, but few people will read it or respond to it. I think the success of sites like diabloprogress shows that such dbs are very appealing to players.
A lot of duelers use diabloprogress to find opponents or to check what other people use. It is far from optimal though since you can only check for pvp-dummy score which doesn't tell you if these players are even dueling. It is completely useless to find opponents that don't have high-end gear because players below top-20 dummy are most likely pve players.
Diabloprogress is mainstream and for a lot of players it's the endgame of D3. I think we all agree that pvp should be recognized as the endgame of D3 and a "pvpprogress" version of diabloprogress would certainly help to get there.
Right now, you won't be recognized as a pvp player unless you sign up for a league. I'm sure that a lot more than the current ~50 players actively playing in d3cl leagues still actively play d3. 50 players, that is like 10% or less of the players registered on here. And then there is a large number of pvp players that didn't even register because they didn't like the rules, the league system or whatever.
That is just the "inner circle" of players that are already into dueling. There are thousands of players that would certainly love to duel if there was some kind of match-making or more incentives.
I think it's pointless and a waste of time to create some match-making/hidden mechanics for the current league system due to the lack of a players.
This site needs a solid foundation first which would be the suggested database. I don't know how much work it would be for you guys to build something like that, but seeing that you already thought about it, it looks like it's not impossible to do
Once you have that it's a lot easier to set up leagues and tournaments of different tiers and rules.
Incentives like gold per win sounds more like farming than pvp to me, I don't think that's how you want to attract players. Where would that constant stream of gold come from anyway?
I think just the database alone would give many incentives. PvP-Dummy score is already an incentive for some players, you could easily add scores to that (d3cl score, mirror duel score, vs class score). The players with the highest score in a category could receive a title (e.g. barb slayer for the highest vs. barb score). Trophies for league and tournament wins could be shown.
The database could improve match-making a lot too. A "find opponent" button that shows you opponents that are likely to be a good match could be done. It could be based on pvp-dummy within a certain range and/or some of the other scores (like the score vs. your class).
Of course there a plenty of options to offer gold and items as incentives then. League and tournament prices, raffles, wager matches and so on.