I found this:
SR71040A, a MIPS64 600Mhz, superscalar embedded microprocessor represents the highest value in terms of performance to the dollar available in the MIPS64 architecture today. The SR71040A complements SandCraft’s SR71010A, the industry’s highest performance production released MIPS64 CPU, by adding a lower cost option to the SR71000 family of processors. The SR71040A utilizes the same CPU pipeline as the SR71010A, but with smaller caches and in a lower pin-count package.
The SR71040A provides an upgrade path for users of the R4000 and R5000-class processors in low to mid range embedded systems, and also enables SandCraft to address more value oriented applications, including enterprise LANs, Storage Area Network systems, security processing systems, remote aggregation systems such as DSLAMs and wireless head ends, and office automation products (laser printers and multifunction peripherals).
These processors are $20 USD in lots of 10,000.
I doubt that they are in a compatable package though...
Here's a link for more info: http://www.morphoses.com/portfolio/sand ... 040.ai.pdf
256 pin TBGA package
The VR5000 is a 223 pin Ceramic Pin Grid Array. Maybe an adaptor?