As far as I know, this is the only Face Invaders cart :)

[ventrra]

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1381014824

[MattyXB]

I think this is wrong. You can buy them by Hozer for US $11.00.

Here the link:
Hozer Face Invaders (http://webpages.charter.net/hozervideo/atari/faceinv.html)

Maybe noone esle has buy it, then this is the only one. But you can easy buy them there, and you will get the same. :D

[ventrra]

Exactly my meaning :D

[slapdash]

I think Barry should have said "a game I hacked from Space (er, Pepsi?) Invaders" rather than "a game I designed".