After running the extruder nozzel into my glass clip, I was determined to find a better solution. Enter SUGRU, a silicone based putty that hardens overnight, retains elasticity and resists high heat. I simply placed Sugru on the edges of the glass plate and heat bed and let it set up overnight. Now I have a surface with no obstructions. I implemented this in May 2012, and have used it with no problems since (still working April,2016). My heat bed runs at 100 degrees C.
I have no affiliation with Sugru, but I think it's a great product.
Sugru can be purched in the USA here: https://sugru.com/us/buy
Open the sugru pack and place the sugru as shown in the picture.
Let it set up for 24 hours
In addition, I bought a black Plumbing/Soldering/Torch mat at Home depot which I placed between the plywood base and the heating bed. So the layers are: plywood base, plumber's mat, Heat Bed Element, glass plate.