Erik:
I'm not convinced with Phytec. Expensive modules may be applicable for 1 to 5 up on product. And on top of that the 89C668 seems to be pretty much just another 8052 with only 6x clocking. 64K FLASH is nice but Cygnal offers now all the way to 128K. And you should look at how beautiful of design job they did with the on-board bank switching for dual use of the FLASH as XMEM and CODE. On top of that it looks to me like the debug support is not that great. From what I can find it looks like it is still monitor based debugging with the capability to do just code execute breakpoints if you live with re-programming the block of code in FLASH where the break point is placed. (Correct me if I am wrong).

I like the Cygnal because it is so nice to be able to debug toward the deliverable program image without having to modify it in order to debug it.

Have you read a data sheet for the likes of a C8051F020 which is a similar match on FLASH size to the '668? If not I would be curious to hear what you think after you looked it over.
Michael Karas