Faction Money Boost

Dear Bukkitdevs,
We are busy setting up a new map on our factions server. In the old map we had diamonds for money and a player shop based economy. Now it's time for a change. Our players request an admin shop and a whole new economy, which we intend to deliver.
So far we have introduced the faction bank (players can send money to their faction), the admin shop and the coin based economy (you can sell stuff in the adminshop, but you also get a few coins/hour). Players with a rank get slightly more money compared to normal users. This is where our problem starts.
Our request
In our quest to solve the issue 'new players/users are rejected by most factions', we came up with the idea of giving 'money boosts' to players in factions with more people. In what follows I will describe te current system:
Now: ranks get 15 to 25 coins/hour, depending on their rank. Users get 10 coins/hour. We will change this once the economy is up and running. Everyone can create a faction for up to 25 players. This will grant you almost no economical advantages. Players depend on what they earn themselves and are able to deposit it in the faction bank if they want. Users are often unwanted for their low income.
This is how we would like to see it: From the moment your faction reaches 5 players, all players in the faction will receive a money boost. They will earn x% more money/hour. If the number of player drops below 5 again, they will go back to earning their normal wage.

1. faction 5+ players => x% money boost
2. faction 10+ players =>x+x % money boost
3. ....
4. ....
5. Faction 25 players => 5x % money boost

This way, factions will be more likely to recruit any players for the benefit of all.
A second function we would like to see is money/day for a faction, based on the number of players.

1. faction 5+players => Y money/day for the faction bank
2. ....
3. ...
4. ...
5. faction 25 players => 5Y money/day for the faction bank

Anyone up for it?
(sorry for my bad English! If you don't understand, feel free to ask!)