As a small business owner, I know the important of measuring workflow in regards to schedule and money. I know the crunch that can happen if things don't happen when they are scheduled to. Because of this, I offer several options to my small business customers:
Flexible billing: I typically bill the 15th and end of every month for hourly projects but am flexible on these terms.
Hourly rate: While I do have set hourly rates for specific tasks, I do offer a reduced rate for retainer/escrow jobs negotiated on a monthly or quarterly basis. Included in this are "rollover" hours so that hours not used in a month can be rolled into the next month and you do not lose them.
Confidentiality: I am willing to sign any confidentiality agreement you require, but please be assured that it is my policy not to disclose any information regarding our work, your company or other correspondence unless authorized by you for a specific purpose (i.e. project management use.)