The only thing worse than "Away" status after 10 minutes is being "Available" all day and then not replying for a few hours or days.
OP: Here's an option to trick your messaging app into thinking you are there for as long as you want:
Granted, you'll have to fucking be at your desk for a few more months before the device arrives, but you can program it yourself to make you as "there" as you want to be.