Hey! Glad I stumbled on this thread because I was about to post a new thread about SMB app hybrid method. I'll post some of the things i've learned and done.
Some of the niches to target: Auction houses, Antique dealers, Specialty hospitals, Child care centers, Mental health professionals (Counselors, trauma care experts, etc), Pharmaceutical companies and of course Restaurants.
Auctioneers, Antique dealers...are businesses that rely on repeat customers. They keep in touch with their clients via email/snailmail/telephone and it is easy to position a mobile app as an alternative to their combined customer contact processes (and a cost effective one at that). I have also tried to pitch an app to a veterinarian/pet supplies client who is keen on the idea.
I have sold apps to a diabetes care specialty hospital and two child care clinics. These hospitals deal with clientele that has a great need to follow a medical regimen. I bought the source code of a diabetes medication schedule app, hired coders and customized it for my client. I also rejigged the same code, customized it for the child care clinics. I can actually continue modifying the code to target other similar specialty hospital niches...
I'll admit that I have only pitched and sold apps to my existing offline SEO clients. Creating a business plan and cold calling new clients will entail a different level of difficulty...but the market is there and it is still untapped. I am also not a coder and you are...so, you probably will find it much easier to conceptualize app ideas and estimate the costs involved...So, it's been a while since you started the thread..have you managed to land a client? Do keep posting and bounce off ideas...thanks...