Here is one locally at a sign shop with logo.
Then there is this guy. Charges off mileage for gathering materials, trips to fabricators and of course miles of testing aftermarket, skids, steering rack mounting brackets and tie rods and a few other items. Until they come up with a flat rate tax these legal deductions need to be used to offset income if you don't have much to deduct otherwise.
If you make an effort to make it a legitimate business and pay your taxes on income you need a paper trail and show you are doing business as a "DBA" type business. The IRS loves paper work to justify their existence.
Besides, the comments you get are really interesting!