Take any of the other suggestions and focus more on creating a service specific for startups. Don't create some "tool" that can be configured any way the user wants, but a service that does it the way it should be done with as little thought, energy, and effort as possible.
Example: If someone already knows how to setup an accounting system or hires an accountant, they can just buy QuickBooks. This isn't going to give the startup a competitive advantage; its just a necessary evil to do business. What is an advantage is having your accounting system already setup for them.
There has to be more in common among startups to setup an accounting system than there are differences. The service should literally lead them through the process of setup with as many decisions made in advance. "But I want to use my personal checking account for the business." Well, you shouldn't. Step #1 Provide the following information and an online checking account will be created at Bank X for Company Y with PayPal, Visa, MasterCard merchant account, etc. Step #2 Employees on payroll? Do this...
Take a LAMP website. Here is the Server Name\Website, Database Server\Database Name. Now do a backup to your offsite datacenter under an appropriate schedule and send the user an email showing them how to do a restore and make them test it. Done.
Again, just do it using the best practices. Why reinvent the wheel? A startup has plenty to worry about. Save them from themselves.