There are two kinds of physical keyboard users: those who never touch the 10-key area (that's the bit on the right that kinda looks like a calculator) and those who will only let you take their 10-key away when you pry it from their cold, dead hands. There's a reason you see a little add-on USB 10-key in that one aisle at Best Buy: data entry experts, especially those that work with Microsoft Excel, need those extra keys like Texans need 15-round ammo magazines. Well, 10-key addicts, Microsoft is here to help you nurse your addiction on Android.
Redmond has just released Keyboard for Excel, which is (wait for it) an Android virtual keyboard designed to be used with Excel. The big selling points here are the previously-mentioned 10-key number pad and a permanent Tab button, which is essential for quick navigation of spreadsheets, plus a vertical row of common spreadsheet modifiers. Right now the keyboard is specifically labelled as an "experiment," so Microsoft has omitted things like auto-correction and gesture typing, on the assumption that you don't need it to edit a bunch of expense reports.
The bad news is that the keyboard only works on tablets... which really isn't so bad, since its ultra-wide layout really wouldn't make sense even on large smartphones. The good news is that it behaves just like a standard third-party keyboard, so you can use it on any text field that takes your fancy.