ADC/DAC

How many bits, or how many db, how many channels?

For straightforward SA's at 12 bits with SPI interfaces, Microchip is probably your cheapest bet.

But I think you may like to look at the Analog Devices website. Here you will find Analog Microcontrollers (12bit ADC's and DACS in a chip with an ARM7 40MIPS core, for example), or look at thier DSP chain where you will find ADC's designed to synchronously feed the DSPs.

Trouble AD is they are hell bent on using the most awkward chip packages possible. You may like to have a look at TIs similiar offerings for ADCs and DSP cahins, don't think they have anything like the analog microcontrollers (yet).