"but would be interested in an apposing win by a taxpayer deducting legal fees in similar circumstances."

As a Business Deduction? You might have a further complication such as, the employee typically gets a payment in consideration for the termination that includes a do not compete clause.

Have you spoken with their attorney? This specific clause is not really a tax issue but a legal one.

Meanwhile, you can certainly read resources and even case law, over the web. You don't even have to go to the local law library to read case law. You used to have to do this for State guidance, for example.

Search the web, such as:

https://www.thebalancesmb.com/non-compete-agreements-and-tax-deductions-398967

http://www.scnoncompetelawyer.com/noncompetes-in-court-attorneys-fees/