I wrote the index CSS on this board last year - >>>/vaps/
you *can* emulate the 2ch-style post numbering via CSS hacks; this is what I did with the index:
.active-index .reply:nth-of-type(3) .intro label .name:before { content: '2 名前：'; }
.active-index .reply:nth-of-type(4) .intro label .name:before { content: '3 名前：'; }
.active-index .reply:nth-of-type(5) .intro label .name:before { content: '4 名前：'; }
.active-index .reply:nth-of-type(6) .intro label .name:before { content: '5 名前：'; }
.active-index .reply:nth-of-type(7) .intro label .name:before { content: '6 名前：'; }
.active-index .reply:nth-of-type(8) .intro label .name:before { content: '7 名前：'; }
.active-index .reply:nth-of-type(9) .intro label .name:before { content: '8 名前：'; }
.active-index .reply:nth-of-type(10) .intro label .name:before { content: '9 名前：'; }
.active-index .reply:nth-of-type(11) .intro label .name:before { content: '10 名前：'; }
.active-index .reply:nth-of-type(12) .intro label .name:before { content: '11 名前：'; }
.active-index .reply:nth-of-type(13) .intro label .name:before { content: '12 名前：'; }
if I were to write the CSS for reply mode I'd basically need 750 of those lines to make it look legit. that's about as good as you're gonna get, don't expect it to be an official feature especially since jim already gave hotwheels all those 2ch boards and they're dead as fuck