Thanks for the quick responses. My first idea was to use multiple sockets but looking a the variety of pics I have at home of the different pin counts I saw that they all had the same basic pins so I was going to go with just one socket with an "adapter". But looking at it some more I just lucked out. I'm now looking at a design that is similar to the PICDEM 2 plus board maid by Microchip http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en010072&part=DM163022
. It has most of the features that I want but not the way I want it configured. I will make several daughter boards that have the peripherals but keep the ribbon cable design to it just because it will allow me to move the projects without breaking the parts off. I'm thinking of ether using several 40 pin ribbon cable connectors to do the jumping to each daughter board, or just having one and each daughter board would have two and just run it from chip to chip like a bus. I'm Just not sure how many chips I could cross before I started to get too much interference. I may go with a larger cable to add more possibilities to the design if I go with the parallel method. To deal with pics with different pin configurations, I'm thinking of having two headers and two ribbon cable connectors. The ribbon cables would be used or "standard" wiring, and the headers would be used for custom configurations.
I'm still thinking of ways to configure the ribbon cable parallel system. I think I'm going to just standardize the the ports and the internal peripherals that most of the chips have in common; like the 5 ports, the esuart, the spi, usb, and the programmer lines.
So the bus would be something like this:
2-9. Port A
10-17. Port B
18-25. Port C
26-33. Port D
34-37. Port E
38-43. PicKit pins (this will include the second vdd vss on some chips) The rest of the pins will be whatever is needed as they are really just be crossovers from the pins that are already connected through the port pins. But could be used for extra i/o of daughter boards or things like usb.
46-48. sdi, sdo, sck