My experience...
I own a stock 1992 Vulcan 750 with around 20,000 miles on it. It's a little rough cosmetically, but has been well maintained, and runs very well. The only "known" issues with these bikes seems to be the stator/rectifier and the shaft drive-IF it wasn't lubed right from the factory...
NOTE: One of the best places for info on the VN750 is here:
Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
It's ironic, but if it weren't for the fact that my stator burned up and proved to be no small hassle to repair, I probably wouldn't be here. (There is a ton of info regarding stator repair hassles/testing/replacing etc. at the website above so I won't bore you with it all here, and save my fingers from typing blisters :mrgreen

. It's because of this that I went out and bought my Spirit.
Ok...with that out of the way.
I found the Vulcan 750 to be a great all-around ride. Very quick in that old-school metric cruiser way-great gearing and downright freakin' "zippy" off the throttle. At 5' 6" I needed/wanted something lower to the ground than my previous GS650 (30" seat height...), but without sacrificing too much performance. The VN750 (Vulcan) is light and handles really well with the Metzlers I have on it. I can scrape pegs and centerstand all day long and she eats it up. At my weight (180 lb) I have no problem keeping up with or leaving behind any bike I've ridden with of the 'cruiser' type. Now, two-up riding isn't as fun, but she can do that as well.
Which leads to my next comments...
The Vulcan 750 is a SMALL bike as far as the seating position and pegs are concerned. While my 29" inseam (hahah...) fits the peg arrangement just fine, I can't imagine anyone with a normal stature being comfortable on a long ride with the stock setup. Even at my size I find myself pushing back
over the step in the seat to stretch my legs out. This is impossible while riding two-up, as the seat length is so tight my passenger is literally "on my back" and banging helmets if not paying attention. Passenger pegs are virtually unusable for a normal inseam, and will find your passenger begging for mercy after no more that an hour tops. (Peg extensions are available to lessens this effect...).
Now at your stated size of "6' 6" 280lbs", I think you'd be crazy to consider a Vulcan 750! You'd be better off with an old-school standard like a CB900 or even an old Gold Wing! Heck, even one of the older 650s would probably fit you better.
The bike has a relatively long wheelbase which can fool you into thinking it's roomier than it actually is (is accomplished by raking the front fork out a few degrees). But trust me-it's tight, and much tighter than my '99 Spirit 1100.
Overall, I still really like mine, and plan on getting it back on the road to use as a daily driver so that I can save my Spirit for two-up riding and longer jaunts. When I jump on the Vulcan after riding the Spirit it feels 100 lbs lighter and the response is much more sport-touring than the more sedate (dare I say "lumbering" Spirit?). The Vulcan vibrates way less, and I can actually use the mirrors over 45 mph! When I get on the Spirit after riding the Vulcan, I feel like I'm on a "big bike" that I can stretch out on and actually carry a passenger comfortably on. Each bike has it's merits and I enjoy them both.
Lastly-with all the beautiful STOCK Vulcan 750s out there I would avoid going anywhere near someone else's "bobber project". If you want a bobber-BUILD IT. That way YOU control exactly what's been done and how. Most "bobbers" I've seen out there are done by kids with hacksaws, black spray paint, and wire clippers. There's just no way I want my hard-earned cash going into something like that. Any bobber done right (and they are out there), should not cost you LESS than what a stock bike is going for-a sure sign it aint right in my opinion. So if you want a bobber someone did up properly, find a guy who knows what he's doing and buy his. Again, just my opinion-but as mentioned already above-the guy in that ad doesn't seem to know what's up with that bike. On top of that, it's "been sitting" which only adds to the probability of trouble.
Just some things to think about....