If you're working 60 or 80 hours per week churning code, surely you have some code to show. </sarcasm>
Really now, the fact that you can't showcase what you've done for your previous company is an implementation detail. Using a portfolio to judge a candidate is perfectly valid and works great with other industries. The reasons why you don't have one are your own concern.
Like I said in other comments, interviewing is (for better or worse) a game / competition. You need to optimize for success.
