We're kicking around some thoughts and wondered if there was consensus out there. In considering a loan to pay income tax expense for someone who is a small business owner or a farmer, would it be considered a business purpose or consumer purpose loan?

Who owes the taxes? If it's the individual (sole proprietor, for example), then regardless of where the bulk of the taxable income comes from, it's a personal obligation of the individual, and I would treat the loan as a consumer loan.

If, on the other hand, the tax obligation is owed by the business as a separate entity (corporation, etc.), then the loan is probably going to be to the entity, with a co-signature or guarantee, and I'd treat it as a business-purpose loan.