I just found this link inside the google checkout page. It may finally be a way of reaching those with the right power to make the decision to support Ubercart for google checkout. Here is the link (hope it works):

https://checkout.google.com/support/sell/bin/request.py?hl=en_US&contact...

Let them know what they gain by supporting Ubercart.

If the link doesn't work, this is where I found it:
checkout.google.com
Tools > Integrate an existing Shopping Cart > Recommend an eCommerce partner