VCC trace routing on a two-layer board with TQFP chip
If your Vcc is properly decoupled it's as good as ground. (There is no such thing as too much decoupling!) I would have no problem routing it underneath the chip. Make sure you have capacitors on it close to the chip's pins, and keep the Vcc traces as short as possible.  

If you get into trouble routing the thing you could use zero ohm chip resistors as jumpers to keep traces as short as possible.