Even when it comes to B2B, it is better for a service like this to get into enterprise via their geeks than try to appeal to their suits, because Tarsnap's strengths mean nothing to a suit.
I do consulting for hedge funds in NYC. Most of them use an accounting system called 'Advent Geneva'. This particular software solution has a Unix component where the actual accounting data lives. My clients would like to back up this database securely and reliably. Security is extremely important as for a given hedge fund, their trades and positions are extremely sensitive information. Tarsnap is exactly the backup solution these clients would want to use. As a consultant, I don't think I will ever be able to sell Tarsnap in its existing form to these clients. Keeping aside pricing, these clients would want an SLA (and other legal stuff mentioned in the article) for the backup service. These clients are more than willing to pay costs associated with this higher level of service and will benefit tremendously from using Tarsnap.
I do not know any backup solution which is better than Tarsnap and it's unfair that businesses will have to use less-than-ideal technical solutions ONLY BECAUSE Colin doesn't want to adjust 'business side' of his product offering.