2 suggestions.

The first one (rate button for giving rep), its already have in mobile. ^^
I know cause i use my phone to give rep some cool fags. :poop:
Tho, it's a bit hassle cause i make my phone in Landscape because..nvm, you can see it for yourself. Haha

For you togive repa user in mobile: Just visit the profile page of the user you want to give rep. There, you will see a "Options" button located in the Cover. Just click the "Options" button and you will see "Message ,Rate and Send Credits".