Backstory: I was chatting with a friend of mine that owns a medium sized print shop, 4 locations, ~45 employees, and he mentioned his troubles finding a CRM that wasn't $80k like netsuite. A lot of the smaller ones don't have specific features he needs and fall short in a lot of places.
The Idea: A niche CRM for print shops.
Deep Dive: Shop Vox, https://www.shopvox.com/, is one of the closest in this space but my friend mentioned the lack of multiple warehouses, poor reporting and a few other missing features caused him to not go through with the product.
There are a few others but hitting on the multiple warehouses is a huge feature. Shopify launched "locations" to manage multiple locations late this year and they have yet to build out all the features. Keying on features that are lacking in these CRM's while staying in the $20-40k/year price range could be a great niche.
Validation: My friend has noticed this gap in the market.
Monetization: You could charge per seat so the software scales with your customers..