[cageyjames]

Maybe I'm missing the point, but aren't there tons of 3rd party clients available as well as their own Highrise client?

http://basecamphq.com/extras

I'm not fan of Basecamp, but I think they've got a good ecosystem going.

[bdclimber14]

They have their Highrise client that they hired a contractor to develop on iOS, and decided that it wasn't worth repeating for their other products.