Illiteracy sucks doesn't it.
LMB EAS-300 case - you can purchase the case from HdB Electronics (650-368-1388) in single unit quantities. Your choice of natural aluminum or black anodized. This is where the Group Buy orders for the case were placed.
Or you can get the EAS-300 Enclosure [style 4006 - 4.124" x 1.582" x 6" w/ heavy radiused (H) ends] at: http://enclosuresandcases.com/sbspecpage.html
You might also try Fry's, they have one that measured 6 x 4.17 x 1.56. It costs $15.95.
Nylon Screws - 4/40 - Digi-Key P/N H550-ND - 0.0926ea. & Nylon Nuts - 4/40 - P/N H616-ND - 0.105ea. You need 6 of each, but there is a 100 minimum quantity for each from Digi-Key. You can try locally, look for them in hooby shops that sell radio control hardware. You CAN substitute steel screw hardware. Just be careful with the plastic FETs, make sure the metal screws do not cut the plastic and short things out. For the flyback transistor and the voltage regulator there is no worries - the only thing you may want to do afterwards is put a dab of fingernail polish or similar on the screw/nut interface to help prevent them backing off due to vibration.
LED mounting clips - Digi-Key P/N 4304MC-ND - 0.08ea. You need 3, but there is a 100 minimum from Digi-Key - try locally.
Cable - You will also need a 'straight-through' DB-9 cable to connect MegaSquirt to your computer for set-up and tuning. Digi-Key sells suitable cables:
AE1020-ND is 6.5 feet long (2 meters) annd sells for $5.35,
AE1021-ND is 9.8 feet long (3 meters) for $6.01.
Either will work, or you can pick one up locally. Look for a VGA computer monitor cable.
Sockets - If you are new to electronics assembly, you may want to solder in sockets for all the chips. The kit includes a socket for the 40-pin CPU. To socket the others you will need:
AE7216-ND ($0.72) for the MAX232 (U6)
AE7208-ND ($0.35) for the MC34151 (U7)
AE7300-ND ($0.43) for the 4N25 (U4)
The sockets allow you to correct your mistake if you install an IC backwards, and also prevent too much heat from transfering to the IC while soldering.