http://home.micros.users.btopenworld.com/zx80/zx80.html
A. you wont find it expensive unless you plan to go into production, RELATIVLY speaking the components will be more expensive, but you will be buying older tech thats cheap and plentiful anyway, you will not be using custom chips or surface mount tech, so no big deal..it never stopped me.
B. in the UK try Maplins or Radio Spares (websites available),
http://www.maplin.co.uk/Sub_Category.aspx?Menu=3&doy=3m9
http://rswww.com/cgi-bin/bv/rswww/home.do?cacheID=ukie
elsewhere try for something like Radio Shack, ram and parts will be cheap enough for hobbyist stuff, just don`t expect to make a MP3 player as small as the one you see in the market unless you plan on using surface mount technology, which will involve a huge outlay in equipment or contracts to have the stuff built.
C. there are a lot of online references for electronics enthusiasts, and some modern electrical CAD software uses databases of standard components and can show you what the device you have drawn up will actualy do when you power it up, interfaces for computer circuits tend to be all TTL (5v) and standard except where you need to convert, eg 16bit to 8 bit or rs232 to usb or binary to decimal digital led display etc, all pretty simple to someone if they "grok" the idea behind modular design and programming etc
D. programming for the cpu you use can be done in emulation on the pc you are sat at now, most makers provide development kits for this purpose freely since it allows the prospective buyer to try before they buy, once you have the final program sorted and working as you want you can send the result to a prom burner or some firm that will burn em for you for testing in the actual device.
E. try the designs in the first link I gave (he mentions several other computers at the bottom), the zx80 was used for a whole host of things in the past, that big rear port that allows open access to the main bus etc allows for immense possibilities (joels couple of hundred leds would be cinch for some simple bus decodeing and a driver array all driven by twenty or so lines of sinclair basic), I have seen some quite elaborate robots run by a zx80, when I was younger I made a controler for a large shop window display train set that allowed for automated schedules etc, easy as pie (well...it worked third try
)
F. not that I have played with this sort of stuff for the last 10 or so years, but you might want to check out PIC controlers, they where the up and coming thing back then (although they might be old hat by now...
)
the average IQ is 100...but the people that took the test where trying to look smart. most people don`t go over 50.
Area 51?, I`m more intrested in what they have in areas 1 to 50
