I'm using client 0.8.6 but this issue has existed for a while. I am aware of this bug, but I don't think it's applicable since I'm still having the issue: #1242
I installed bitcoin-qt from the PPA. When I launch it, via my .xprofile file using the arguments -min and -splash=0, I INCONSISTENTLY get no tray icon. I see the process running, but without a tray icon, I essentially can't switch to the app.
I understand AwesomeWM on Ubuntu is a little bit of a strange setup, so the main issue to address is that the tray icon randomly shows or doesn't show on boot.
If it's any help, litecoin-qt has the same behavior. If one icon shows, the other shows as well. The behavior is linked to both.
Please let me know if any debug/output info is needed.