They've got a few more Exustar models at Kathy Watt's place in Black Rock. One of the cheapest ways into carbon models that you'll find and haven't found any bad reviews of the brand. They're a Taiwanese manufacturer who used to do some of the Shimano range.
The specializeds at TFM would be worth a look with the sale. We tried a few of their mtb shoes out last week and they seemed to be their road shoe with a bit of tread stuck on, which sounds like it might meet your needs.
Or if you're like me and have a bonus burning a hole in your pocket, you could order a set of the Sidi Dragon's (can't wait until they arrive)