I spent all of 2014 building a SaaS for dog daycare/kennel owners. The MVP turned out beautiful. Went to a few trade shows towards the end of last year and people went crazy over the software. 0 outbound marketing yet, and already have 22 customers at $100/month. This year my goal is to scale up to 200 customers. It's a really weird market niche where no one has built software for in 10 years. Pretty neat.
Any specific reason for it being dog only - we put our cats in a cattery fairly often when we travel and I'd love to be able to use an online system to book things.
Not only can you manage your reservations online, we also feature photo/video report cards over SMS :). That's my personal favorite feature...love getting a video of my 2 dogs wrestling at daycare.
We have a pretty generous referral program, get in touch if you have a business you'd like to refer.