Gear300 said:
Have there been any proposals of plausible experiments for any of the heavily studied Quantum Gravity models?
There was a 5-day workshop in Stockholm this July on Experimental Search for Quantum Gravity. The organizer was Sabine Hossenfelder and she recently posted a write-up of what she took away from the conference.
I think the short answer is yes
proposals but nothing immediately pending that you would want to hear about.
You could read Sabine's summary of the conference---as I recall there were about 24 papers presenting different ideas for pursuing QG experimentally (and by astrophysical observation).
http://arxiv.org/abs/1010.3420
Experimental Search for Quantum Gravity
Sabine Hossenfelder
(Submitted on 17 Oct 2010)
"
We offer a brief survey of existent and planned experimental tests for quantum gravity. First, we outline the questions we wish to address, and then introduce some of the phenomenological models that are currently used in quantum gravity, both with and without a lowered Planck scale. After that, we summarize experimental areas where these models can be tested or constrained and discuss the status of the field."
Comments: This article is partly based on the talks at the workshop on Experimental Search for Quantum Gravity, Stockholm, July 12-16 2010
There was also a ESQG conference or workshop in November 2007
http://www.perimeterinstitute.ca/esqg07/
You can find the list of speakers and talks there. Maybe also videos of talks.
Here is the website for the July 2010 ESQG conference
http://prime-spot.de/ESQG10/
It has abstract summaries of each of the 24 papers that were presented.