If I may be so bold; been there done that. If you are supporting "one man band" businesses you are going to go insane and broke. They don't provide enough business to keep food on your table, they whine about every invoice, and they don't provide a consistant revenue stream. Begin to market your skills to businesses with 10+ or even better 20+. It will only take a couple of those customers to make your SMB consulting business thrive. You will need to provide them maintenance every month. Once you break into the 30+ market you'll be there 6-8 hours every week.
In the meantime checkout datapreserve.com and get your clients on an off site backup program and make certain that you are servicing your clients at least quarterly to verify backups, check for issues in the event log, run disk utilities like chkdsk and defrag and blow out the dust. Describe this to them as a 3,000 mile oil change. Check the belts, hoses, fluids, make reccomendations to improve their business performance and they will value your expertise and interest in their business.
Take some Microsoft cert classes and get the certs. A few years from now you'll be supporting longhorn SBS servers. you will have helped the "one man bands" to graduate to a 10 - 20 person company by understanding their business goals and prescribing technology solutions to help them acheive great sucess. Your reputation and profits will flourish. Grow your expertise in supporting servers and become a Microsoft Partner. Also check out SMBnation.com, I hope that it works out for you, good luck.
Keep Up with TechRepublic