Don't know about the H4 thing, but by removing the gametype .bitmaps from the shell folder and trying to compile, I got an error pointing to a .tag_collection:
ui\ui_tags_loaded_multiplayer_scenario_type.tag_collection
Quote: From debug.txt:
11.19.13 11:34:04 tool pc 01.00.09.0620 ----------------------------------------------
11.19.13 11:34:04 reference function: _write_to_error_file
11.19.13 11:34:04 reference address: 42ca20
11.19.13 11:34:04 ### the biped 'ag\characters\block_wall\block_wall' has no 'head' marker
11.19.13 11:34:04 ### the biped 'ag\characters\block_wall\block_wall' has no 'body' marker
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_background.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_background.bitmap'.
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_icon_ctf.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_icon_ctf.bitmap'.
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_icon_king.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_icon_king.bitmap'.
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_icon_oddball.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_icon_oddball.bitmap'.
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_icon_race.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_icon_race.bitmap'.
11.19.13 11:34:05 file_open('c:\program files (x86)\microsoft games\halo custom edition\tags\ui\shell\bitmaps\team_icon_slayer.bitmap') error 0x00000002 'The system cannot find the file specified. '
11.19.13 11:34:05 couldn't open bitmap tag 'team_icon_slayer.bitmap'.
11.19.13 11:34:05 failed to load tag_collection tag 'ui\ui_tags_loaded_multiplayer_scenario_type'
11.19.13 11:34:05 failed to load ui tags tied to multiplayer scenarios
11.19.13 11:34:05 WARNING: 1 clusters in structure_bsp ag\maps\asdf\asdf have no background sound or sound environment.
About 3 slots down in the file are where the .bitmaps are being referenced. It doesn't seem to give any options or control over
where the bitmaps are anchored, however.
This sounds about right, because I vaguely remember some time ago someone was trying to alter these images, but didn't have much luck achieving their H3-like hud.