I found several evergreen dwarf hollies for color,
but that produce good winter berries. Millane Nursery has 'compacta' but that can get up to 4'. Any cultivar that stays at 3' without continuous shearing?
'Helleri' Holly stays at 2-3 feet but no berries. Japanese Skimmia (not a holly but similar)-the female has beautiful winter berries but it grows 2-4 feet. Most of the hollies or berrying plants I can think of grow to 4 feet-that's a tough one. Will let you know if I can think of any others.