You've got a lot more to think about than what type of items you'll bake. Hopefully, you have great passion for baking and an excellent business background and sales ability.
Owning a bakery is the most difficult of all culinary professions in my opinion. The monotony of making the same rolls, croissants, muffins each day drove me insane.
As with ANY business, your product is secondary to your sales and marketing ability. I'd work on my sales material and why prospects should switch to your products. Why are they better that competitors? What is your pricing structure? How does your food cost fit into your profit and loss statement? How will you produce, deliver, bill, and collect for your clients? What part of the day will you spend baking and what part will you spend making sales calls to get new clients. How much money do you have to keep your business afloat during the 6 months to a year it will take to break even? Will you have insurance against people claiming food illness? How about insurance for your delivery drivers and your delivery van?
The biggest mistake people make is thinking that customers will just call them because they opened a bakery. Sorry for the tough love, but nobody will care as much as you about your bakery. You'll need to spend a considerable amount of time SELLING.
If you want a REAL business, you'll need to start a REAL business. Sharing someone else's kitchen, or worse yet, baking from your house gives you a hobby. Get a bank loan, get a partner/investor, but create a business that looks respectable and confident. It will definately hurt your sales to look like a guy that's "just trying this out" by hiding in someone else's kitchen. You need to BRAND your new business and promote it before you bake a single loaf.
Perhaps bake some samples each day, and bring them to the businesses you've targeted as good prospects. Follow up each day for two weeks to prove how great your products are, and how you can be counted upon to deliver each and every day.
What will you need? Geez... big ovens, lots of loaf pans, sheet pans, mixers, a dish machine to clean up, health department certificate, packaging and labeling materials, coolers for ingredients, a food distributor to buy ingredients wholesale....on and on. Don't forget, your prospects are re-selling your items, so they want them as cheap as possible. They want to make more profit off your items than you will.
This is not an endeavor to make an emotional decision upon just because you like baking. You'll hate it quickly if you don't prepare your business before you bake. Read Malcolm Gladwell's "The Tipping Point". He relates a story of a woman who baked fantastic pies, opened a business that became successful, but the quality suffered the bigger she got, eventually hating the business because the emotion of beautiful baked goods was gone quickly. The cheap labor she needed to hire didn't give the loving care to her products that she did.
You say you want to be in wholesale baking, yet will share a kitchen. What happens if your company is as successful as you hope? You get orders for 400 loaves of bread, 1000 croissants, and 1500 muffins every day? Do you have an expansion plan? How about staff in this situation? How will you produce this much in a timely fashion?
Don't forget, your product is stale by the end of the day. There is a tremendous amount of product and money waste if you don't have an air-tight production system. It would be an equal shame to bake 50 loaves each day and throw away 35 of them.
I'd suggest looking into a franchise like "Great Harvest Bread". It's an investment upfront, but you'll get all the support you need, from formulas to marketing.