dave,
sounds like an interesting project.
thats quite a few lights to power!
good thing with incandescent lights like this you can power with ac or dc current. your power pack would not put out enough to power all your lights -- will need 7 amps to power 100 70ma lamps. you can easily drive them from a simple wall wart transformer. to do 100 of these would probably take a few of these as most times these transformers are like 2 or 3 amps max.
you can probably get away with using a 5v power supplies for these the lights will just run a tad dimmer, but you might actually want this as driving them at full power may be too bright. you could use a variable dc source like a train power pack, but again these are limited to around an amp or so around 6v. (the 7va rating is basically saying voltage x amperage = 7va) if you have any wall warts laying around that are 3-6 vdc range you might try your lights on them by just touching the wires to the plugs and seeing how they look. there are other more sophisticated ways to reduce the voltage if you want to get into that as well -- you can use a resistor to drop the voltage for each bulb but you end up with more components in the mix to deal with. the simple method would be to just use wall warts that are the voltage that gives you the brightness you want.
if you use a 5 or 6v transformer then you can just wire all the light bulbs in parallel.
i would first experiment with what ever voltage adapters you have laying around and see what gives you the right brightness on your bulbs first. then buy one that voltage and string up a group to it to see how it all looks. you also want to probably just wire different areas together of like 20 lamps into a single switch and 2A wall wart. you dont want to draw the max amperage of the transformer rating, give it some buffer of like 25%.
these are pretty cheap
http://www.ebay.com/itm/New-Home-AC-Wall-Power-Adapter-Charger-PSP-US-Plug-100-240V-DC-5V-2A-Brand-/370582275937?pt=Video_Games_Accessories&hash=item56486cc761#ht_4629wt_882post some picts of the layout, sounds interesting!
cheers
jeff
