Hi I'm having this exact problem and have done some debugging:
When making a new SMS there's three steps 1: you first select recipients 2: then you write the body of the SMS 3: you schedule the SMS
Between step two and three the table civicrm_mailing_recipients correctly gets filled with email_id set to null and phone_id set with the id of the contacts phonenr. This gets done in the function getRecipients in CRM/Mailing/BAO/Mailing.php, and the phone_id's get set because $mode is set to "sms". But after completing step three this function is called again (don't know why?) and $mode is now empty, and the email_id is set instead and phone_id is set to null. This results in an empty result from an sql-call in the function deliver in CRM/Mailing/Bao/MailingJob.php, and thus there's no one to send to.
I don't know why this second call is made or why $mode is empty the second time around.
I know this is not a complete answer, but it's a very good clue to whats wrong, and I don't have enough points to comment, so here it is. Lets figure out exactly whats wrong, and file an issue with a patch :) PS: If you need to send SMSes right now you can cheat by scheduling the bulk sms to a few minutes in the future, then choose continue on the scheduled sms at the page with planned and send SMSes go to step two where you can Edit the SMS. Now open another tab/Window and run the send scheduled SMSes job from there. The bulk sms will be send because the table with recipients is correctly filled at step two and only overwritten with nulls after step three.