Hi Theoryman, the PAL issue has been resolved so I'm sure Michael will be releasing the design files very soon. There are plans for a production run by one member, don't know if this will be bare boards, kits or turn-key builds. The Gerber files will be open HW so anyone can do a run of boards. Most board houses will have a 10 board min so a group buy would be best.
I would suggest that if you want a kit wait till it's announced before ordering the basic parts, the cost may be better due to volume discounts and having all the needed parts from one source is saves a lot of headaches. Most likely the chipset, U1MB, UAV and FTDI BOB will have to be sourced but I would hold off
The harder to find parts are listed here, but if kits are available I would recommend waiting.
You will need a known good chipset- CPU, ANTIC, GTIA, PIA and PoKEY (2 for stereo). You can either use a donor Atari or buy NOS chips.
The ANTIC and GTIA both need to be either NTSC or PAL, you can't mix and match. Also the (NTSC) ANTIC can be the older CO12296 or the newer CO21697, the older one is cheaper from some sources.
If you are going to build a PAL version you will also need the Xtals 3.546894MHz and 4.433618MHz. Check at Best as these are not so easy to find. For NTSC you will need a 3.579545MHz but should be able to find it at Digikey so wait for you other BOM parts.
U1MB, will have to change the RA headers to straight one. So if you don't want to do the de-soldering, contact someone to help. I believe Stephen has offered to help with this (earlier in this thread).
UAV ver C or ver D have both been tested, when ordering from Bryan request the XEL headers, all 3 SIPs are 'pin-2-pin'.
Sparkfun FTDI BoB 12731
You'll also need the 64K SRAM chip UM61512A. Will have to search Ebay, I ordered from this seller http://www.ebay.com/itm/391377191204and http://www.ebay.com/itm/371081620321
3 PICs- 2 16F1847 and a 16F1571. These need to be programmed with the firmware, If you can program them then buy them blank but otherwise you could ask here or buy from Microchip Direct and have them factory programmed. I would wait as there are still firmware updates in the works.
Cart connector-http://www.ebay.com/itm/140888497123and ECI connector-http://www.ebay.com/itm/10pc-Industrial-Card-Edge-Slot-Socket-Connector-7x2P-14P-2-54mm-0-1-3A/141501565005?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
There are also the RCA and S-Video stacked connector and PS2 KB and Mouse stacked connector. The SIO connector or you can use a DB-15. A DIN 13 RGB connector, like on the Atari STs, optional.
Most everything else can be ordered from Digikey and will ship fast, so wait for the BOM with the updated list.