possible change to tree pane

[FredeF]

The + and - signs are very large,dominant and bright in the tree view.
Is it possible to change this? It would also be nice to have dotted lines between them instead of the solid ones, again so they are more discreete.
As you can see, I have replaced the ugly and dominant Win7 folder icons with the nice XP ones.
I have attached two screenshots. #1 is from MC and #2 is from another file manager.