Have always wanted something like this, I pray that it will come with the new system. Since guild houses are rarely used as guild houses(mine is rarely open at all). I would like for this to be a feature in the new system, and probably have it cost a decent amount of points/currency. And you could avoid the donation problem by having it cost the points the guild has, so then people couldn't waltz in and donate.

And that also is a good idea, having the leader be able to select who can buy/edit the guild house, and who cannot.

Individual rooms for individual members would be neat, though im not sure that if it costed guild points instead of gralats how exactly you would pull it off. The benefits of points Vs. Gralats would have to be examined more thoroughly