Nth-ing the "could Sudbury support that?" worries. My father owns a clothing store in Belleville, which doesn't have the Northern Ontario effect but does have the small-city thing going on, and what you describe would have a hard time getting by in Belleville. You really need to do up a full business case for the store, doubly so if you're going to operate on a business loan, but some things to keep in mind:
Who are your customers? Does the age and income range you're selling to stick around Sudbury, or do they get out the first chance they get? Sudbury has had a population decline, especially at the younger end, for the last decade, with most of the exodus heading towards southern Ontario. (There were only 5,000 men aged 25-35
in Sudbury in 2001.)
Where are your potential customers shopping now? If they're hitting up Wal-Mart you'll have a hard time getting them to come to you instead, but if they're making twice-yearly trips to Toronto to shop then you might be on to something.
What's your competition at exactly your price point? If there isn't any selling the styles you're thinking of selling, maybe
you've struck it rich, but it's more probable that no-one else has considered it profitable. If the competition at the price point is, say, all aimed at over-40s, then that's probably important to consider.
What about at a lower price point for your demographic? If people are shopping in Chateau or Old Navy now, you'll have to figure out if they're doing so because they can't find anything nicer-and-more-expensive, or if they're just happy with Chateau and Old Navy quality and price. The average individual income for residents 15 and over in Sudbury is only $28,000 so you want to make sure they're even able
to step up a level in price point.
Lastly, be very, very sure that you're opening the store because you think a lot of other people will give you money for the things you sell, and not just because you wish someone else would open the store you want to open. It's easy to wish someone sold the lines you want to carry locally and then figure that if they're not going to, then YOU will! -- but it's a lot harder to get people in the door and leaving with your merchandise.