A couple of points here; first, I can't think of a reason why you can't have a very broadly based business that both makes a product and lets you do consulting, thus running everything through the LLC. Think of diversified corporations, even United Parcel Service both delivers packages and sells logistics consulting services employing people who never touch a box.
Second, when I started my partnership LLC with my spouse, I used a CPA for the taxes for the first couple of years since I didn't know business taxes. I was able to deduct the cost of traveling to and attending a training course for my field before I started the business. As has been mentioned, there are limits on how much money you can deduct that way, and there may be a 1 year limit on how far back you can go, but I was definitely able to deduct business expenses in a year before I had any business income. Now, if I had never brought in any business income in later years, I might run the risk in an IRS audit of having it declared a "hobby" and retroactively losing that deduction, but I had more income the next year than my previous year's loss, and have continued to run it as a real business, so from what I've been told it would all be fine per IRS guidelines.