I also have a X748, 60" 7 iron deck and a snowblower.
The54" snowblower is great. I have it raised about 1 inch up to keep it from eating gravel. I'm not a big fan of the plastic impeller. I wore down a little last year. This year I've only used it once. It took about as much time to clear the drive at with the mower and blower than with a 4320 (1971 model) with a 7 foot bucket.
The 7 iron deck is great. The spindles are huge! My last JD was a 318. They have really sped up the blades. It sounds like a helicopter. When I'm in the shop and my friends kid is mowing, I have many times times thought what the heck is that noise.
I plan on keeping this thing 20 years. This deck is capable of lasting that long. (I also have the 62 inch deck in the shed)
I never thought of using one of those cables on the pout pitch. It's a very standard cable of various legnths for John Deere. I have a couple used ones on the shelf. They use it for hydraulic levers, transmission shift levers and such. I'm curious what the lever on the tractor looks like. It guess it's a nice feature, but I set the spout to blow the snow far far away. I don't know if there is a time when I'd want to blow it closer. If I'm close tot he house, I swing the spout the other way.
Also have the John Deere weight box. Filled it with steel beer bottle molds. Each mold is about 66 pounds. There are ten of them in the box. I can't say it's really necessary though. I never got stuck last year without the weight. 4wd is all I need, except when I was too close to the ditch and got sucked in. Having the extra weight now will probably make it suck into the ditch easier now.
Oh yeah, I also use the PTO on bin augers.
This is the best lawn mower I have ever owned. I can't imagine how Deere could make it better. I wouldn't care for the new ones that are full time 4wd.