Do you have experience in working in the retail industry? And by retail, I mean the wholesale side of the business, whether it be for a brand or retailer? It's one thing to assess the cost of production but marketing and geting buyers to buy your goods would be another. I am sure you've already accounted for all these costs in setting up a brand outside of what you want to create. Traditional menswear is very difficult, especially for ecommerce.
I can't speak for anyone else who works in the industry but I can't tell you how many times myself (I'm not a buyer) or my buying counterparts have said no to brands time and time again whether it be in person, mailers or emails. And I can't tell how jaded the term 'menswear with my own twist' sounds. It's tossed around so much that it's so weightless.
In no means am I trying to be demeaning or showing some type of negative tact, but just be sure that at the end of the day, you should be making money. I don't post much here but frequently browse this thread b/c it's interesting. I see a lot of bad mouthing on styles when in actuality, these are the styles/trends that sell best. It's the 80/20 rule: 20% of your inventory does 80% of your business, the rest falls by the waistside.
My best advice would be to go to a tradeshow like Magic or Project/Pool (Project would be your best bet) and see how many damn lines are out there trying to get off the ground or are doing the exact same thing you want to pursue. Good luck with your venture.