That sounds like an interesting approach there, Matt.
Any chance of getting a writeup on the specifics? (including any notes you have on how you're planning on doing costs)
Here's what I got so far. One of the players is about to complete his Stronghold, another one is just starting his.
Strongholds & Roles
Strongholds enhance your Role, making you a more effective Leader, Striker, Controller, or Defender
A Character cannot gain a stronghold before 7th level. A stronghold can either be granted to a character as a reward for some extraordinary service on behalf of a local Noble, he can build a new stronghold from scratch, or he can repair an existing ruin. Once his Stronghold is complete, he becomes a Lord, gains powers based on his level, and attracts followers. Followers will be covered later.
Strongholds grant power enhancements. One power enhancement at 7th, 10th, 13th, 16th, and 19th level. Power enhancements can only be applied to Encounter Attack Powers or Daily Attack powers. The player picks a new power to enhance every time he gets a power enhancement.
The character gains one power enhancement upon recieving or completing his Stronghold. If the character is higher than 7th level upon gaining a Stronghold, there may be additional power enhancements available, but he cannot access them until he gains another level.
For instance; Cho-Tuk builds a keep in a swamp. He is 11th level and when the keep is complete, he immediately gains the 7th level power enhancement. When he reaches 12th level, he gains the 10th level power enhancement. He will not receive another enhancement until he reaches 13th level.
The 7th level Enhancement affects one power, an attack power, either a daily or an encounter power. The player cannot change which power has the enhancement until he gains a new enhancement. Some enhancements are cumulative, some replace older enhancements. In the case of enhancements that replace older enhancements, the player can choose to stick with the older enhancement on a power-by-power basis, but this decision must be made when the character gains a new enhancement and cannot be changed until he gains another one.
Every time his character gains another enhancement, an additional power can be enhanced.
Controllers
Controller Strongholds, such as a Wizard's Tower, enhance attack powers by inflicting additional conditions on any enemies hit by them. The conditions last until the end of the Controller's next turn.
Level 7: Prone
Level 10: Dazed
Level 13: Weakened
Level 16: Immobilized
Level 19: Stunned.
In other words, if Velorin gains a stronghold, at 7th level he may chose one Attack power, either an Encounter or a Daily, and anyone affected by that power is also knocked prone. At 10th level he may now have two enhanced two powers, and anyone affected by them is Dazed. He my choose, upon gaining 10th level, to have one or both powers knock his targets prone instead, but he must make this decision when he gains 10th level, and cannot change it until he gains 13th level.
Defenders
Defender Strongholds, such as a Fighter's Keep, enhance attack powers by inflicting enemies Marked by the character. The conditions last until the Mark goes away.
Level 7: Slowed
Level 10: -2 to all attacks
Level 13: Weakened
Level 16: Immobilized
Level 19: Blinded
Strikers
Striker Strongholds enhance attack powers by increasing the damage done to enemies hit by the power. They are cumulative.
Level 7: +1 to critical range.
Level 10: +5 ongoing damage (save ends)
Level 13: +1W
Level 16: +5 ongoing (total of +10 from Stronghold Enhancements, save ends)
Level 19: +1 to critical range (total of +2 from Stronghold Enhancements)
Leaders
Leader Strongholds enhance attack powers by aiding the Leader's allies, even if they were not affected by the power normally. The Leader may choose any ally he can see to gain the benefit of the enhancement. The ally he chooses gains...
Level 7: Temporary HP equal to twice his level.
Level 10: Regain the use of one Encounter power.
Level 13: Remove one ongoing effect.
Level 16: Gain an action point (this does not allow the ally to use two Action Points in one Encounter)
Level 19: Bonus to his next attack equal to one half the Leader's level.
These effects are cumulative. But the Leader may only apply one per use of the power. For instance, Ottavio the 10th level Warlord may choose, upon using his enhanced Daily power, whether to grant 20 temporary HP, or allow his ally to regain the use of one Encounter power.