We also route some local traffic to other local ISPs via frame relay now. Our 56k offering presently is through a port reseller, MegaPOP and uses a separate T3 backbone network. That said these are some concerns and some things I am currently planning on doing to address them. They are not set in stone, or even thick mud. They may change before they are implemented.
Several problems exist with that platform.
SparcLinux has a bug that prevents it from working with two CPU modules. If the bug in SparcLinux is not resolved in the near term we may move Eskinews to an SS-20 to allow us to use four CPUs. The higher bus speed of an SS-20 would also improve performance. The cost of electricity is going up and the cost of hardware is coming down and at some point it's just not going to make sense to keep paying the electric bill on the old hardware. This would improve latency during heavy traffic conditions.