Ooooh,
I like the idea of connecting pin 13 to +5V to skip the bootloader. You might need to disconnect it to upload code, but that's better than needing to disconnect RX just to reset the board. Especially because pin 13 is probably only rarely used as an input (although it is one of the SPI pins, which might mean that it gets tied high sometimes).
I nerver dared to ask for this, because I always thought this idea was put down a long time ago when I didn't even knew the Arduino existed!
This would be my : "top notch, favourite,I waited for this all my life" enhancement to the Arduino. Acutually it's the only one that comes to my mind!
Let's go, hunt that startup-delay down with an on-board jumper
Eberhard