OK, this may be my last posting on this topic. I've had a couple of weeks to review what information I could get on existing Cell applications. One thing really becomes apparent. This processor is HARD to implement. First, the use of XDR memory makes designing the memory circuits fairly difficult. If you review the PDF I've referenced before on the IBM/Mercury designed Cell based PCI-e board you'll note that when the memory circuits of that board were designed, Rambus was contracted to assist in the development. XDRs archetecture and the skew on the XDR memory bus increases the difficulty of implementing this type of memory. Its worth noting that while the Cell could potentially address 32 to 64 GB of memory, the largest current designs are limited to 1GB.
This of course does not take into account the PowerXCell 8i use of DDR2 memory, but that processor is far out of our reach economically.
Second, because of the complexity inherent in the design of Cell based boards, it does not seem possible to implement a Cell design with a simple four layer motherboard. Instead, most designs would likely be eight or more layers. This would greatly increase the complexity and cost of the design.
Further, as the Cell uses an expansion bus called FlexIO there are few options for interfacing peripheral circuits. Currently, the only southbridge available is a chip that Tosihiba and Sony refer to as the "Super Companion Chip". This chip is used on Toshiba's Cell Reference Set (and the Cell Reference Set 2) and on Sony's BCU-100 multimedia rack system. It may also be related to internal components in the PS3. Information related to this chip is simply not available.
When IBM, Mecury, and Fixstar have designed Cell related products they have designed their own glue circuitry to accompany the Cell. So, we have a processor that requires custom designed interface circuits (rather than the "off the shelf" components we've seen in the past).
None of this makes implementing a Cell design impossible, it just makes it much more difficult. It also may explain IBM reluctance to offer this product to the general public.
The last response I've received from IBM tends to reflect this. Ray Bryant is IBM's Director of Games and Power Solutions. Part of the message I received from him states these facts.

"a) There are no STI restrictions on IBM's right to sell BE chips for applications outside game consoles

b) IBM has not invested in the engineering work and documentation to support Cell BE as a standard, off-the-shelf component product that would be available for sale to anyone. That decision was based on the limited interest we saw in the market for high volume sales of this highly specialized multi-processor design.

c) IBM has supported usage of Cell BE chips in several custom board level applications for OEM clients, typically as part of a broader relationship between IBM and those clients beyond Cell chip sales

d) IBM continues to review specific client requests for access to Cell BE chips as loose components and makes case by case decisions based on the level of engineering support needed to assist the client in Cell based system design, the size of the business opportunity for IBM, and the strategic benefits to IBM of the project. We currently have several active client engagements where IBM has quoted sales of loose Cell BE chips for projects that met IBM's strategic business goals."

So, where does this leave us? IBM examines and qualifies each potential application for the Cell. While we could present a business case to IBM, they might reject the proposal if the application didn't have the potential for relatively high sales.
At his point, I don't think we can offer that opportunity to IBM so I am (at least for the time being) not going to pursue this further.
Jim