OK + Suggest feature. Rated 5 out of 5 stars

Awesome! Working great in my XP with FF 21.0
A• A toolbar button to call the Findbar when i an smooking, or drinking the coffe. :)
B• Options to changue the background and text color of the input, for diferent states.
C• Option to enable close the findbar by doble click in it.
D• Option to changue the font color of all other words that are outside the input. (not really important)
E• Option to hide the "Search:" word near the input, or replacing it with a 16x16 ico or png image.
F• Option to make the imput width a 50 or 100 % More large.

Anyway, it, ok. Thanks for your enfort on this explendid stuff.

This review is for a previous version of the add-on (1.0.1). 

A) Already in version 1.1 ;)
B and D) I think are better left for themes rather than changing in the FBT preferences.
C) I don't know about this, the toolbar button kind of provides the same functionality with a single click, plus you have the close button and the keyboard shortcut... But it's not really a bad idea for customization, I'll consider this.
E and F) I like these ideas, I probably will implement them sometime in the future.