The cache is soldered to the board, so yer out of luck there. In theory, the Aladdin 5 could cache up to 512, but the early chipsets had a flaw in the cache tag RAM that caused the 128 MB limitation.
There are many other benefits to the dual V-Cache structure that are being overlooked. One benefit is due to the way that AMD designed the Infinity Fabric interconnect between the core complex die (or ...