>>It needs to be a tablet held app with local data, there will be some interaction with the web, but it can't be a web hosted app.

If android, the logical choice is sqllite that is used by Android itself for storage. If you install the Android sdk you can write apps without an IDE at all, but you'd be better off with Eclipse which is the official/expected choice for Android.

However, consider that over the next 3-12 months, realistic cross-platform options are slated to arrive. One example getting attention is Lianja that allows the same codesource to be used for traditional desktop apps, served browser apps and cross-platform mobile in beta and due later this year. The desktop/IIS version is due to release any day now. Lianja has some more standard language options including python and Javascript plus some surprising other options.