All right, put this aside for a while but I am back to it. Thanks for your thoughts on this. Yes, avoiding SE tax is the goal.
What I am finding in my research is that the level of activity here falls into a grey area as far as whether it is sufficiently continuous and regular. In Powell, T.C. Memo 2014-235, I find
Petitioners failed to show that they conducted the North Carolina activity with sufficient continuity and regularity. In 2008 and 2009 petitioner husband worked full time for WPL. On average he worked approximately 45 hours per week. Petitioners received income from WPL. Petitioner husband spent approximately 10 to 15 hours per week developing the North Carolina activity. (emphasis added)
Although the Powell case is distinguished because in that case there was no profit and here there is a small amount of profit, I doubt the client's activity is at this point more than 10-15 hours per week. Like in Powell, the activity in question is not related to the taxpayer's main occupation and source of income.
In Cameron, T.C. Memo 2007-260 referred to above, the court found that 109 purchases and 103 sales through brokerage accounts during a year was not "substantial." As I mentioned, however, I do concede each eBay sale would involve more work than a stock sale.
In Maximoff, T.C. Memo 1987-155, an activity of 20-30 hours per week was considered to be a trade or business, but I don't think this activity consumes that much time.