I did it. The tweak is actually quite simple.
This is the code it's needed for a dropdown tab. Notice it's slightly different from a normal bootstrap dropdown tab:
<ul class="nav nav-tabs myTabDrop">
<li id="tabOccrs" class="dropdown">
<a href="#" class="contentTab dropdown-toggle">Tab (<span class="tabsel">option1</span>) <span class="crtOpenDrop">▾</span></a>
<ul class="dropdown-menu">
<li><a href="#dropdown1" data-toggle="tab" class="subtab">Option1</a></li>
<li><a href="#dropdown2" data-toggle="tab" class="subtab">Option2</a></li>
</ul>
</li>
</ul>
The jquery script we need is the following:
$('.myTabDrop span.crtOpenDrop').click(function (e) {
e.preventDefault();
$(this).closest("a")
.addClass("dropdown-toggle")
.attr("data-toggle", "dropdown");
});
$('.myTabDrop a.contentTab').click(function (e) {
e.preventDefault();
if(! $(e.target).is("span")) {
$(this).removeClass("dropdown-toggle")
.attr("data-toggle", "")
.tab("show");
}
});
of course further little tweaks are needed, but this is a semi-complete solution (and graphically complete)
UPDATE
I created a jquery plugin for this need. Enjoy using it