Under the letter of the law (Origination Clause), I believe that this will be found Constitutional. After all, the "bill" did originate in the House. However, under the intent, I think it's not Constitutional. After all, the "tax" did not originate in the House, but was inserted in the Senate. And, it's not as if the Senate merely modified a tax that the House had proposed (ie: changed the amount, changed to whom it applied, etc.), but they created a tax.
Ultimately, I think Obamacare is around for good. It won't be struck. Much to my dismay.