Bobonli, to me, a road bike is a road bike and a cross is a cross. A cross bike is closer to a mountain bike - but with drop bars, no suspension and skinny tires. You can do what you want as far as moving the cable guides and allow for more clearance, add disc tabs - but still have cantis......and.......you'll have a cross bike (or a very expensive custom roadie).
Cross bikes (Moots anyway), don't handle 'slower' than a road bike. Road bikes are quicker, steeper. It's hard to explain - Porsches are super quick and responsive - but, you don't venture off-road on them. Jeeps are fun off road, can climb like goats, but on a long road trip - those knobby tires and super taught suspension make it painful. Old school Cadillacs, while super comfy, were, uh, old school Cadillacs - lull you to sleep as you wallow around a corner.
A Moots cross bike is like a Porsche Cayenne - strong on performance - and still off road capable. As a disclamer - I'm no car guy, but you get my drift.
It's not a road bike, it's not a mountain bike- it is a flat on cross bike and a very nice one at that - the Swiss Army Knife of bikes, just how you mentioned. Very off road capable, very on road fun (with the right wheels/tires). Wheelbase and angles are very 'bike type' oriented. Longer and slacker usually mean more predictable and stable. Conversly, shorter and steeper usually mean quick/agile - but more unforgiving. If it's your only bike, you'll never notice it, but if you switch between bikes, you'll most definately feel the difference. It's by no means a better or worse ride or a slower/quicker ride - it's a 'different' ride. The cross bikes get a totally different tube design than a roadie. Longer, wider, 's' bend stays that facilitate tire/ankle clearance, a little higher bb, slacker angles for a more stable ride characteristic. Moots definately has longish top tube and steepish head angle on their crosser (read: racy). I love it.
That said, it is a very traditional cross bike, top tube routing allows different configs as far as brakes (lots of cross guys reverse front/rear braking - something that internal routing does not permit??), cables/housing easy to replace, impeccable workmanship fit and finish - none better on the planet. I'm a big, big fan - I think I'm on my 4th Moots cross? Something like that.
Options: that Rogetk asked - I'm big on a few. Custom geometery, can get it with/without the chain stay bridge, different bb's - can get the standard threaded/english or BB 30, single speed dropouts, cable guide options, rack and fendor options (I deplore rack and fendors on a Moots road or cross - I know some swear by them....but there are commuter bikes for a reason), 44mm headtube (I think on the standard frame - and definate on the RSL), coupler option on the standard, 3rd bottle mount, etc., etc - it's on the website -but they don't mention the bb or headtube option. I also love that they can add a longer head tube than 'stock' at no charge - so if you want a centimeter longer headtube - it's very doable. disclamer: 'within reason'.
Also, about the brakes. Cross brakes used to be laughable. They were simply on to slow you down and horrible things they were. Now, they are making some pretty decent stoppers - Avid, TRP, Paul, etc. But, discs are coming and I would bet the farm that within 2-3 years, high end cross bikes (and roadies) will be hard to get WITHOUT discs.
So, Bobonli, you can probably tell I like cross - from reading your 'wants' above, I don't think there is any doubt, a cross bike is what you need. Very off-road capable (within reason, of course), fun and very capable on the road, good commuter, but not a crit machine. I personally think Moots makes the single best cross bike on the planet - bar none - and in two versions. Lots of people on this forum say that if they could have just 'one' bike, it would be the crosser. With your wants, and with any option you may have/need, you can't go wrong.
One note: being it's absolute prime time building season in the high end bike world, you may have to wait a bit.....