Definitely get the WACOM digitizer and the XRITE color calibrator. It doesn't matter if you won't ever need it and it's only a $150 add-on. This will secure the resale value by a LOT more than a $150. It's all perception. Just in case you need to convert it into cash at some point, you'll want to have that.
You're right on the money getting the 820QM over the 720QM, but the 920XM I am not so sure about. That was especially true before they dropped the upgrade price to $750 over the 720QM, but it may still be an unnecessary option. Speaking of potentially unnecessary options, I'd think twice about getting the FX3800M graphics card option for the same reason, but if you have a need for it, or if you think you might have a need during the time that you anticipate owning the W701, then obviously, get it, since you say that price is not a primary consideration.
Getting the 500GB 7200rpm drive is exactly what I'll be doing as well considering the bang you get for that upgrade buck. I also happen to agree with your overall decision to get the W701 over the M6500. I looked at that model as well, but frankly, it seems overpriced for what it is, and, perhaps more important, what it is not and does not have.
Definitely don't get your RAM or an SSD from Lenovo. Unless you have money to burn, that's just plain well...unnecessary.

Especially since you are getting the full 16GB of RAM.
Someone else will have to tell you as to whether or not you ought to go for the FX 3800M for $470 (+tax), and the i7-920XM for $750 (+tax), and the (+tax) part will be another $119 if you live in L.A., for example. It's bound to be less most anywhere else in the U.S., but just tack on another $100 to the cost of both of just those two upgrades! Again, the WACOM digitizer and the color calibrator are two tangible upgrades that you can see, feel, and touch, and in the case of the calibrator, it'll even make some cutsie funny noises. $150 (and a lot lower +tax part) for both of those is a noooo-brainer. And I don't mean to suggest that the graphics card and the i7-920XM aren't tangible, too, but to see it, you have to open the thing up, so it doesn't have the same effect.
Excuse my partially cynical stance, but I've been running my own company for a long time and I've witnessed some very odd decision-making processes on the part of some of my customer, including even business accounts.
I'm in the same boat as you. I had a W700 and sold it a little too early, because I thought the W701 would be out a lot earlier than it did. Now I'm back on my own trust T60p.

With Lenovo, you never really know these days. I've also decided against the M6500 as well as the MacBook Pro, which I briefly considered. I've waited this long, so I'll wait a few more weeks to see if HP's new workstation, the 8740w, will indeed come out with the promised DC2 (DreamColor 2) display, which will also feature the RGB LED backlight, but will allegedly also have over 1 billion colors, with a 100% color gamut, as well as IPS display technology. There are a few people on here who have doubts, but too many other other things that I predicted did turn out to be right on the money. One thing is true, however, which is that HP is wayyy late with its release of this breakthrough DC2 display. It was supposed to happen "sometime in May", and when I called their procurement team on it late last month, they gave me a new date of "mid-June". Well, I've waited this long, I can wait another 2-3 weeks. If they don't come through then, I will likely pull the trigger on a W701 as well.
Now you need someone else to share their knowledge and opinion(s) as to whether or not you'll want the i7-920XM and the FX3800M. If you wait a while, you'll be able to get the i7-940XM. However, you can always wait a while for new technology to come out, and you'll end up never getting anything if you go that route.
Good luck to you.
15-inch Core 2 Duo ThinkPad T60p | Ivy-Bridge (Late-2012) Mac mini w/ quad Core i7-3615QM 2.3GHz, 16GB DDR3-1600MHz RAM, 240GB+180GB Intel 520 Series SATA III SSD's, 5x3TB Drobo 5D