Bowhunter,
I have been thinking about this and I definitely applaud you for two things:
1. Realizing that the gun is not always gun to be the answer. WAY too many people think just because they have a gun they are safe. I would say that 75% of my students would be overwhelmed by a determined attacker a close range before they ever got to their gun.
2. Still being interested in your responsibility for defense despite your health issues.
That said, you are obviously working from a deficit. It is counter-intuitive, but still true, that those with the most serious physical problems are the ones who ned the most close quarters training. A 24 year old SEAL is much more likely to be able to use awareness and athleticism to be able to get to a CCW pistol than a 63 year old overweight car salesman. I'm much more likely to have the young guy in an Extreme Close Quarters Tactics course, but Wilford Brimley is the guy who really needs the skills more. Both Mike Janich an I would welcome you into any of our courses, but you might also consider attending training offered by Shivworks,
http://www.shivworks.com/tutorials.asps. At this time I do not have any ECQT courses scheduled for civilian students, though we are looking into some options to have my Regional Reps start hosting the courses later in the year. Meanwhile, I know that Shivworks would welcome you into a course and give you some great training. I trained with him last year and there were a variety of body types and athleticisms represented, including one wheelchair bound participant.
At the end of the day, of course, no one is going to work magic. If you can't use your core strength and torso to generate force, maintain balance and otherwise keep your opponent from hurting and controlling you, that is a fact of life you will have to accept. Well Rounded Close Quarters fighting training, including knife and pistol work, are available from a variety of sources. Good Luck.
-RJP