I spoke to Denny at Turnbull's store today. He said they've been getting inquiries on fitting these. He said they estimate $350-450 to fit them which includes any forend functional and fitting issues.

Dean, it is still a product they hope to sell, hopefully at a profit for the company. As such, someone in the organization may take the initiative to take a set on the road, or not. They somehow made the hard business decision to take an A-10 on the road in the hopes of getting some interest.

Well, they haven't much time or many venues to display the barrels at considering the announcement has been made that we have until year's end to pony up.
The A-10 was a much stronger commitment, in my opinion, than some (potentially controversial) barrel sets and bringing one around for display was most probably a strong point of the marketing strategy for the A-10.
Are all of the A-10's custom made on a pre-payment basis (as are the .410 barrels) or are a percentage of them being built on speculation?

Probably the same situation for the A-10 as it was for the RBL. "Custom Order Only" but a bunch left over at the end of production to be sold.

There was a whole pile of RBL's in their rack at Greenwich this past Janurary.

Right, and that's how they should display the barrels too - a few of each gauge and length.