This mod replaces the standard, one picture at a time, portrait chooser with a screen that shows 10 pictures at a time. The mod is also a part of AncientCowboy's EE UI Tweaks. I took AC's WeiDU code and edited it down to make a WeiDU script to install my mod as a standalone.
Installation instructions: Download the zip file attached to this post and unzip it into your game folder (the one with chitin.key in it).
If you don't have UI.menu in your override already, extract it with Near Infinity.
Run setup-BYMultiPort.exe and follow the instructions like any WeiDU mod.
Now, start the game and you have your new portrait chooser.
In the portrait screen, you can click on the portrait or the button underneath to choose the portrait. The smaller arrows move forward or backward one screen, while the big arrows move forward or back five screens (50 portraits). The portraits wrap around just like the standard chooser does.
This is fully functional and should be able to handle any number of portraits.