Hmmm,
the CPU disassemblers for logic analyzers are the old idea. For example the Tektronix 1241 had approx. 20 mnemonics modules as an accessories.
Generally, they use the ALE pin for address/data demultiplexing, M1 cycle pin on Z80 for instruction separation etc.
But I do not think that this is usefull approach for microcontrollers which have the FLASH/RAM integrated inside (PIC, AVR etc.)
For microcontrollers with external program memory, I am sure that new types of Agilent/Tek analyzers have some possibility for dissembler generation.
At least, you should be able to read the analyzer memory into PC and write the disassembler as a PC program.