I believe you can change the size of items on the screen if you tweak the density of your device. This requires rooting your device, and then modifying a text file (/system/build.prop) to input an "incorrect" value for the DPI. If you increase the DPI, you will get bigger icons. The value to change is ro.sf.lcd_density.
Alternatively, you can use this app:
change LCD density. You need root as well.
A note of warning: when you trick your tablet into using a different DPI, some apps in the market may become incompatible and not show anymore, as an app may not look at its best on high density devices and the developer has indicated so when uploading it to the market, so the market will filter out any apps that are deemed unsuitable for high density devices.