I'm so sorry for your loss. I can't imagine going through it. It made me tear up.
I was so sad for you when I read this. My mini rex Houdini had gas back in December 2011, and it was the most horrible experience. He wouldn't eat or drink, and kept laying down on his belly and scooting himself across the floor with his back feet. Freaked me out- and it was on a weekend, and of course, there are NO rabbit specialty vets where I live that are open or even on emergency call on weekends. I was up for 24 hours straight with him. Thankfully, a friend of mine knows a show rabbit breeder and she had some good advice that worked for us. I had been trying to give him water and softened pellets all day and he wouldn't take ANYTHING- not even his favorite treat Craisins. She suggested this: baby gas drops, Gatorade, and banana. I used the baby gas drops 3 times in an hour, as instructed. I gave him Gatorade several times that hour, along with some water, so he had electrolytes. Mashed banana was his solid food. After using her advice, he was up on his own, drinking water, and using his litter box. I was ecstatic. He has a VERY sensitive system and cannot eat ANYTHING out of the normal from his hay, pellets, SOME greens (cilantro and parsley), and the occasional Craisin. His body can't handle anything else.
My female Mama Bun had gas just about 2 months ago and I went through the same thing. Again, did the gas drops, Gatorade, and banana and she was fine after a couple hours. I would suggest this remedy to anyone now.
I'm sorry again, for your bunny loss.