I have 'drawable' folders in 'res' for the different densities (low, medium, high, extra high) which I'm considering. This is bloating my app to 20MB+ whereas if I could build/upload my application separately for each density it would be less than 10MB. Anyone know if this is possible and how?
Yes, you can have multiple versions of your application on the Market that are filtered based on screen density. Google Market filters allow you to accomplish this. Google does not recommend this though, because managing multiple .apks can be a hassle. Here's the dev docs on Multiple APK Support.