SIMD computational model
I've found that Blelloch writes a book about data-parallelism: Vector models for data-parallel computing. In this work, he introduces a vector memory model (V-RAM). This model extends simple RAM with additional vector memory, that available to store an unlimited amount of homogeneous simple data types. Also, there is a vector processor that is capable to perform some "simple" operations with the vectors. Blelloch has a nice definition of the simple operation: he allows to use operations, that can be implemented in $O(n)$ time on RAM and also these operations must be contained in the $NC^1$ class of the boolean circuits.

This model is a very high level, but I think that it depicts the structure of SIMD processing more deeply than PRAM. Also, this model quite interesting by itself, because it wraps almost all parallel interaction of algorithm in the primitives and description of algorithms is purely sequential. 

Does anyone know about the future of this model? Does it evolve or just stuck and no progress in done in this direction?