Android devices are now very popular. You should definitely consider to make an application for android users.
Take a look at the application made for KGS... It's 15$, it does the strict minimum and yet people are buying it! Tygem is a lot better as a server, and you already proved you could make a better app on the ipad.
Anyway, if you decide to make an application for android devices, I'll definitely buy it, and I know I'm not the only one....