1) I have a bunch of AM29F040B-70JC, AT49F002-70JC, and AT49F010-120JC on hand. The latter are good for anyone who just wants a ROM SIMM and doesn't care about experimenting. The middle one provides a moderate amount of extra program space. The first one would be the biggest, but I have fewer of them on hand. Also, the middle one has a RESET_ pin on pin 1, which is NC on the others, so pin 1 needs to be tied high if one uses the AT49F002-70JC. Ah, I see that pin1 is A18 on the 4 Mb chips. That's inconvenient.
Doug, I might be able to lower your cost a bit and possibly simplify your logistics so that you don't feel like you need to stock up on too many chips for your next batch, since I already have several hundred (111, 200, 55 respectively) on hand.
I also have about 3200 AT28C64-25TI on hand, but I don't know what anyone would do with those....
2) The X100 (NuBus PowerMac) ROM module appears to be the same as the X500 ROM module, which is the same as the 7200, ANS, PEx, and Beige G3 ROM module. There is a few pins variation in the latter to change the supply voltage from 5V to 3.3V. I've never traced the whole X100 module out, but the form factor is identical, and I traced a few pins and those that I checked all matched up.
I have designed and built about 200 of this ROM module. I have Gerber files available, but it is a four layer board, so it is expensive to have made. It operates a lot faster than the old Mac II modules and I recommend using at least 90ns Flash on board.
The X100 module is a DIMM and is 64 bits wide. So you either need eight PLCC32 chips on board, or to use wider 16 bit Flash. My design uses four PSOP44 chips which is fine for a fixed module, but not so useful for an experimenting module. I tried installing PSOP44 sockets on the thing in support of the PEx ROM project, but I can't get it to work with the PSOP44 sockets.
The pinout which is in the 68K Wiki is the one I used to build the module, so that pinout is tested, unless I mistyped something.
3) I have no idea if SM PLCC sockets will tolerate oven soldering, but they'd be pretty useless if they wouldn't. In any case, I'd get the manufacturer's datasheet and check that. That information should be readily available from the manufacturer.
4) I should have mentioned the Flash I have on hand before you got to the ordering point, but was off the forums for a while. In case other projects come up, here's an incomplete list of chips I have on hand that might be useful and are almost certainly cheaper from me than from a distributor:
2000 KM4132G512Q-10 SGRAM
310 Hitachi PSRAM HM658512ALFP (512K X
457 MCM6206BA 32K X 8 SRAM
249 M5M417800CT 2M X 8 DRAM
324 Oki MSM514400D 1M X 4 DRAM
800 ISSI 61C632A-7TQT 32K X 32 SRAM
48 Galvantech GVT71128D32T-5I 128K X 32 Burst SRAM
53 Samsung K7N801845M-QC15 512K X 18 NtNRAM
1000 ICS9158-03CW24T-CT Clock Buffer/multiplier chips
660 NCR53C96 SCSI controllers
285 GAL16VD-15LJ (need to check part number, D = 8?)
184 DP83223V (ethernet something or other)
52 DP83840AVCE (see above)
24 Xilinx XC3090-100 PQ160C (good luck finding compatible development software)
75 AM85C30-10JC (serial port controllers)
40 Citizen W1D Notebook floppy drives
5) The Mac II family ROM looks great!
I'm tempted to buy one, but I'm so backed up on projects here, it'd just be another thing laying around. Sigh. I finally started a to-do list the other day and typed out 40 items without even thinking hard. If I could get rid of the fish, the boy, the job, and stop coaching LL baseball....I would be very unhappy, but then I could catch up on the projects.