I've seen two sites in the wild which manage to get Like and Reblog buttons on their homepages via hacks.
This seems to be the best one to reference: http://cicerontheme.tumblr.com/
Somehow, they manage to get the reblog URL, how, i have no idea. I've been rummaging through their code and all I find is this for the like button:
$('a.likeLink').click(function() {
var post = $(this).closest('.post');
var id = post.attr('id');
var oath = post.attr('rel').slice(-8);
var like = 'http://www.tumblr.com/like/'+oath+'?id='+id;
$('#likeit').attr('src', like);
});
It's discussed a little in this Stack overflow discussion but again, does not get to the crux of the matter, how the heck to get the reblog url.
I've gone through the script resources and havent found any personal scripts, just scripts from tumblr, my chrome extensions, etc. Where are they getting it from?!
In the "like" code pasted above, they get the post ID easily enough, you just have to use Tumblrs {Permalink}, but the reblog url is taken from the rel attribute.
Hoping someone can help!
Thanks.
Pretty sure this isn't a JS thing — when you view the source of the site you linked, the reblog links are already there (meaning, they aren't being dynamically inserted).
I think the the Ciceron theme is actually generating reblog links - have you tried adding:
<a href="{ReblogURL}">Reblog</a>
...to your theme?