I can't really contribute from a competing standpoint, but I think that you and I have similar aesthetic ideals and I've had some of the same questions/concerns myself.
You've definitely already got size and strength on me, but I eat very similarly to what jungleinthefrunk described and it works really well for me. I was only around 145 lbs at my absolute heaviest before going vegan, and I wasn't training at that time. I would second the idea that you'll have to diet down really slowly if you don't want to lose your muscle mass. It's certainly difficult but not impossible to keep your macro ratios right where you want them and get in 2000 kcal/day.
I keep my protein high by having beans at every meal, eating as many cruciferous veggies as I possibly can, and keep my fruit intake to 3-4 pieces a day. I'll sit down and polish off a can of beans and a few cups of steamed broccoli for dinner and that's 43g protein/125g carb/5g fat (689 kcal) after my post-workout shake (another 230 kcal, 34g protein/10g carb/6g fat) to total up to 919 kcal, 33.5% of which is protein. The only thing I've found to work for me is to go really heavy on legumes. This leads to a lot of redundant meals which I'm sure would bore some people, but I keep things really redundant and simple for myself 95% of the time so that the other 5% of the time (when I'm eating with friends, going out, etc) I can just eat anything I want and have fun and not think at all about my macros.
I used to lean heavily on nuts for protein until I realized just exactly how much fat I was intaking at the same time. Now I just have a handful of nuts every day and enjoy a tablespoon or two of peanut butter with my breakfast every now and then. I also tend to juice around 75% of my veggie/fruit intake every morning to extend my night-time fasting until mid-morning and to make sure that I've got all of the proper nutrients swimming around in my bloodstream before I even think about eating solid food. I try to be done eating most of my food for the day by about 8 pm, and if I'm hungry before bed I stick with some veggies or another juice.
Not sure if any of this will work for you, but it's been doing the trick for me. Overall I think the idea is just to eat as clean and fresh as you can, stay away from processed junk, and eat as many legumes and green veggies as you possibly can. Calorie for calorie, broccoli has the same amount of protein as a fat-free chicken breast. You've just gotta eat more of it (which speaks heavily to me, as I am practically always eating hah).
Some interesting points you make there! I think both you and Jungle might be right. I weighed myself the other way (thinking I still weighed what I implied in my original post) and turns out I weigh 203 lbs! That means I've gained 30 + lbs since my leaner days where I still pushed heavy (just not as heavy as now). Of course let me be honest- it's not all muscle gain- I do have an unnatural fondness of sweets, so a lot of it is just undisciplined diet. For the past 8 months or so I've sort of been "bulking" which renders me a perma-bulker (yikes!) and if I'm not careful... FAT!
But still a 2000 kcal cut diet is a little bit unrealistic, seeing as my current calorie maintenance (including training) is 4000 kcal +. I think I might start with a 2500 kcal cut diet with as much clean food as possible and a significantly greater amount of vegetables than what I'm consuming now. And for fast proteins I still have two big spans of whey protein powder I can be creative with, maybe make some good smoothies or protein ice-cream.
Also- while idealistically I'd like to go vegan (again)- I realise this is not something I can do overnight and maybe not even in the future... Maybe vegetarianism might be what I can handle at most. Maybe I'll stay a carnivore. I don't know. But I do know my diet needs to be more lean and green- that's for sure!
I guess the reason I found myself drawn to the notion of vegan body-building, aside from the obvious health and humanitarian aspect to it- is because it's fitness with a more spiritual approach to it.
Anyway definitely some good tips there! Vegan or otherwise everyone could benefit from a more green diet!