Concerning the Trafalgar class: I don't think it likely that these would be converted to carry mobile suits. As we've seen over the years, you can carry mobile suits just about anywhere - packed into Columbus transports, stuffed into the cargo holds of Magellans and Salamises, strapped to the outsides of ships - which simply isn't true of fighters. Unless you actually refitted a Trafalgar to provide full maintenance and support facilities for mobile suits, there's no advantage over stuffing the same number of mobile suits into a few Columbus transports, and you'd lose one of the few ships that can actually support and deploy space fighters.
Of course, space fighters aren't really effective against mobile suits, but I do see your point.
Incidentally, if the Federation has 24 Antietam-class auxiliary carriers - these are Columbus transports refitted as fighter carriers, which can carry 25-30 Saberfish fighters each, according to the MSV books - plus 8 Trafalgar-class carriers, which Tomino's novels indicate can carry 60 fighters each, then the Federation's maximum carrier-based fighter strength would be about 1,200 fighters. That's kind of interesting.
12,000 snub fighters? Think about how many Death Stars that could take out!
As for the Zaku Cannon, it's a machine of many mysteries.
Maybe thats why I like it so much.
And finally, that 135mm anti-ship cannon probably isn't exclusive to the Zudah; all the Zudah's other weapons are stock Zaku equipment, after all. If you wanted to outfit a Zaku Cannon for space, and the cooling issues ruled out the use of beam weapons, and you solved the recoil problem by adding leg thrusters, then that 135mm cannon might be a fine weapon to install on its backpack.
Yes, yes it would be a fine weapon. It reminds me of the Xamel a bit, since that cannon is going to take up a lot of space.
Wait a minute...I just had a bright idea.
A Zaku Cannon Space Type, with two standard cannons on its shoulders, wielding a 135mm cannon with its hands, complete with thrusters to solve the recoil problem.
(insert evil laugh here)