I actually ran into this issue as well for multiple posts submissions. You have two options here:
1) Generate a new token AFTER post submission:
Session::put('_token', sha1(microtime()))
2) Redirect AFTER post to a confirmation page:
Redirect::route('form/success')->with("data", $myData)
I ended up doing the second.
EDIT: In a comment via Jason, it may be best to use the combination of both methods outlined above