—: in theory it is possible.
When I made the plugin, I based it out of some JS implementations I had found at the time.
Some of the implementation managed weight.
Here are the links :
46dogs.blogspot.fr/2009/10/star-pathroute-finding-javascript-code.html
niseg.moshela.com/test_maze.html
(there are even more links in the comments of the first one)
Unfortunately I don't have the time/will to add to the current plugin.
Also, doesn't Rez's implementation contain some weight calculation already ?
Anyway, if you feel like modifying the plugin to add the weight calculation, by all means go ahead.