If you don't mind editing alot then go to the Data folder of your install and open descr_model_battle. then change all the lines that say something like:

type egyptian_spearman
skeleton fs_slow_spearman, fs_slow_swordsman
indiv_range 40
texture egypt, data/models_unit/textures/nile_spearman.tga
model_flexi data/models_unit/unit_egyptian_nile_spear_high.cas, 15
model_flexi data/models_unit/unit_egyptian_nile_spear_med.cas, 30
model_flexi data/models_unit/unit_egyptian_nile_spear_low.cas, 40
model_flexi data/models_unit/unit_egyptian_nile_spear_lowest.cas, max
model_sprite egypt, 60.0, data/sprites/egypt_egyptian_spearman_sprite.spr
model_tri 400, 0.5f, 0.5f, 0.5f

to say something like

type egyptian_spearman
skeleton fs_slow_spearman, fs_slow_swordsman
indiv_range 40
texture egypt, data/models_unit/textures/nile_spearman.tga
model_flexi data/models_unit/unit_egyptian_nile_spear_lowest.cas, 15
model_flexi data/models_unit/unit_egyptian_nile_spear_lowest.cas, 30
model_flexi data/models_unit/unit_egyptian_nile_spear_lowest.cas, 40
model_flexi data/models_unit/unit_egyptian_nile_spear_lowest.cas, max
model_sprite egypt, 60.0, data/sprites/egypt_egyptian_spearman_sprite.spr
model_tri 400, 0.5f, 0.5f, 0.5f


or you could press Ctrl+H and in the find box put "high" and in the replace box put "lowest" for every type of draw distance e.g.: med, high, low