You can actually use a unicode trick to allow you to define an alternate ToString method directly against your generic list.
If you enable hex character input into visual studio then you can create invisible characters by holding down the Alt key, then pressing the following on your numeric keypad + F F F 9 (now release Alt)
So we can create the following function with an invisible character placed next to its name... (yes i know its VB code, but the concept will still work work for C#)
<Extension()> _ Public Function ToString(ByVal source As Generic.List(Of Char)) As String Return String.Join(separator:="", values:=source.ToArray) End Function
Now in visual studio, when you access intellisense against your list, you will be able to choose between either the standard ToString or your custom function.
To enable hex character input into visual studio you may need to edit your registry
open HKEY_CURRENT_USERControl PanelInput Method and create a REG_SZ called EnableHexNumpad set this to 1
You will also need to disable the & shortcuts for the File, Edit, Debug, Data menus, In visual studio, open the tools menu, select customize, then open the commands tab, and using the modify selection button for any menu item that uses either of the ABCDEF charactes for its short cut, by removing the &
Otherwise you will end up opening popup menus, instead of typing hex characters.