So fortunately I was able to modify this panel and my skin with the changes included will be available soon.
Here's the xml I used, which is based on the "update a legacy" panel.
Code:
<!-- Taller Legacy Extraction panel -->
<PanelFile ID="ID_UISkin_ItemAdvancement_ExtractLegacy_Window">
<Element ID="ItemAdvancement_ExtractLegacy_Window" X="304" Y="190" Width="426" Height="543">
<Element ID="ItemAdvancement_ExtractLegacy_SelectButton" X="165" Y="507" Width="96" Height="20">
<Element ID="TextButtonReference_Left" X="0" Y="0" Width="20" Height="20"> </Element>
<Element ID="TextButtonReference_Mid" X="20" Y="0" Width="55" Height="20"> </Element>
<Element ID="TextButtonReference_Right" X="75" Y="0" Width="20" Height="20"> </Element>
</Element>
<Element ID="ItemAdvancement_ExtractLegacyListBox_Bg" X="0" Y="0" Width="1" Height="1"> </Element>
<Element ID="ItemAdvancement_ExtractLegacyListBox" X="75" Y="173" Width="270" Height="314"> </Element>
<Element ID="ItemAdvancement_ExtractLegacyScrollbar" X="345" Y="173" Width="9" Height="314">
<Element ID="scroll_bottom_field" X="0" Y="304" Width="9" Height="10"> </Element>
<Element ID="UpButton" X="-1" Y="104" Width="10" Height="10"> </Element>
<Element ID="DownButton" X="0" Y="0" Width="10" Height="10"> </Element>
<Element ID="scroll_top_field" X="0" Y="0" Width="9" Height="10"> </Element>
<Element ID="widget" X="0" Y="10" Width="10" Height="94">
<Element ID="widget_top_field" X="0" Y="0" Width="10" Height="10"> </Element>
<Element ID="widget_mid_field" X="0" Y="10" Width="10" Height="74"> </Element>
<Element ID="widget_bottom_field" X="0" Y="84" Width="10" Height="10"> </Element>
</Element>
<Element ID="scroll_middle_field" X="0" Y="10" Width="9" Height="294"> </Element>
</Element>
<Element ID="ItemAdvancement_ExtractLegacy_Background" X="33" Y="10" Width="360" Height="529">
<Element ID="Base_Box_Silver_TopLeft" X="0" Y="0" Width="36" Height="36"> </Element>
<Element ID="Base_Box_Silver_TopMid" X="36" Y="0" Width="288" Height="36"> </Element>
<Element ID="Base_Box_Silver_TopRight" X="324" Y="0" Width="36" Height="36"> </Element>
<Element ID="Base_Box_Silver_MidLeft" X="0" Y="36" Width="36" Height="457"> </Element>
<Element ID="Base_Box_Silver_MidRight" X="324" Y="36" Width="36" Height="457"> </Element>
<Element ID="Base_Box_Silver_BottomLeft" X="0" Y="493" Width="36" Height="36"> </Element>
<Element ID="Base_Box_Silver_BottomMid" X="36" Y="493" Width="288" Height="36"> </Element>
<Element ID="Base_Box_Silver_BottomRight" X="324" Y="493" Width="36" Height="36"> </Element>
<Element ID="Base_Box_Silver_Background" X="36" Y="36" Width="288" Height="457"> </Element>
</Element>
</Element>
</PanelFile>