[HMBeaty]

My end result



In postbit.css, find:

.postbitlegacy .postbody, .eventbit .eventdetails .eventbody {
    margin-{vb:stylevar left}: {vb:stylevar postbitlegacy_userinfo_width};
    border-{vb:stylevar left}: {vb:stylevar postbit_userinfo_border};
    background: {vb:stylevar postbit_background};
    _background-image: none;
    padding-bottom: 1em;
}

Replace with:

.postbitlegacy .postbody, .eventbit .eventdetails .eventbody {
    margin-{vb:stylevar right}: {vb:stylevar postbitlegacy_userinfo_width};
    border-{vb:stylevar right}: {vb:stylevar postbit_userinfo_border};
    background: {vb:stylevar postbit_background};
    _background-image: none;
    padding-bottom: 1em;
}

Find:

.postbitlegacy .userinfo {
    float:{vb:stylevar right};
    position: relative;
    width:{vb:math {vb:stylevar postbitlegacy_userinfo_width}-{vb:math {vb:stylevar padding}*2}}; 
    padding: 2px {vb:stylevar padding} {vb:math {vb:stylevar padding}/2};
    font-size: {vb:stylevar small_fontSize};
    display:block;
        background: {vb:stylevar postbit_userinfo_background};
    clear:both;
}

Replace with:

.postbitlegacy .userinfo {
    float:{vb:stylevar right};
    position: relative;
    width:{vb:math {vb:stylevar postbitlegacy_userinfo_width}-{vb:math {vb:stylevar padding}*2}}; 
    padding: 2px {vb:stylevar padding} {vb:math {vb:stylevar padding}/2};
    font-size: {vb:stylevar small_fontSize};
    display:block;
        background: {vb:stylevar postbit_userinfo_background};
    clear:both;
}

This code is unsupported and has not been fully tested!