We met the guys at Store Gecko this week. Not tried it so can't vouch for it personally but seemed like really good guys and it may be worth taking a look.
Doesn't Store Manager suit your needs completely? What is the reason why you are looking for alternative?
If Store Manager is our of your budget, please, send me a private message and I will provide you some good offer to buy this app
Most of complex solutions with similar set of features will be SaaS with monthly payments almost the same as our one-time fee.
Please, check your private messages, I have sent you discount as we always trying to meet the needs of interested clients.