Hi was trying hard to replace the kendo panel bar expand and collapse icon with bootstrap glyphicon-chevron-right. One way I can think is using javascript, literally replacing each and every state of icon. I have also noticed that kendo panelbar adds the following css to the span like:
k-icon k-i-arrow-s k-panelbar-expand  -- when collapsed
k-icon k-i-arrow-n k-panelbar-collapse-- when expanded
I have tried doing this
#leftcontentnav .k-panelbar > li > span >.k-icon {
    background-color: transparent;
    opacity: 0.8;
    border-color: transparent;
    display: inline-block;
    width: 16px;
    height: 16px;
    overflow: hidden;
    background-repeat: no-repeat;
    font-size: 0;
    line-height: 0;
    text-align: center;
    background-image: url('../Images/download.jpg');
}
But I have downloaded a glyphicon and even that doesn't work properly.. is there any solution?