Our product has some complexity and customization that needs to happen so we are going to need to own the shipping / warehouse operations for the foreseeable future. I know where to find tech talent, leadership talent, marketing talent, etc. I have no idea where to find someone who knows logistics / warehouse management and wants to work at an early-stage startup. Any ideas would be appreciated!
Recruit from other eCommerce companies. However, it is not useful to try to recruit from Amazon. They have deep economic ties at the level you need (lots of stock) and a very difficult non-compete. You may need to hire a recruiter for this one that has the contacts.
The first place I go for logistics talent is ex-military. Actually, you might take a step back thinking your complexity and customization is what's requiring you to hold warehouse operations internally. You may be making an incorrect assumption that warehouse workers are unskilled or unaccustomed to building products for unique orders. It's not true.
Fulfillment companies come in many grades. Yes, there are certainly the more blunt types. But there are also sophisticated ones that can handle customer service for complex, high-end, and nuances products. It's a matter of what work you're trying to shift and why. I've done training at our fulfillment company so operators understand the types of questions that they're likely to get about products, developed answer sheets that cover 90% of customer interactions, and given them a method of escalating customer interactions to the headquarters seamlessly. There are even two levels of fulfillment operations, the supervisors being the most intelligent for that extra layer between the customer and a call that comes to HQ.
As for building your products, even if you require component assembly, your fulfillment staff can do anything you can do in house. They just need training. You get what you pay for. The biggest advantage of fulfillment is typically the cost reduction for the amount of space it requires to store your products and scalabilty that you get because idle time is not billed as salary. Those workers go do something else when you don't have orders.
If you want a personal recommendation, you can reach out to me directly to talk about what your worries are. I don't like to make blind recommendations hawking for service providers and products.