>I question the size of the market for this kind of thing.

Once you get below a certain price point every low-level employee who has to handle a large amount of cash enters your target market.

They can branch out into "traditional" PPE if they really need to. Work clothing with reinforcement over key areas would be a big hit in some industries (at the right price of course).

>If you feel the need to wear armor every day and can't openly wear a ballistic vest, you might want to consider moving.

Your house doesn't almost catch fire every day yet you probably have smoke alarms. I can see a handgun proof polo shirt being quite popular among politicians on the campaign trail.