As you know when you played fallout 3, your Pip Boy removed part of your armor on your arm, making your character look very odd and disjointed visually. Do you think it would been better to go back to the original look of a PDA rather than an armband version that removes parts of your armor?

I don't think it made him look strange or disjointed, it looked pretty cool. Most likely, Obsidian saw this as NOTHING to worry about. Look at the screenshots.

I had hoped the Pipboy would be a 2000 model (like this unofficial http://i271.photobucket.com/albums/jj125/Gizmojunk/pipboyrend.jpg)

IMO there really shouldn't be a 3000 model as society stopped with the bomb, and the few left were just picking up the pieces.

*If you saw "the book of Eli", you notice that he didn't have a new post-war Ipod.

Actually, I think the pipboy 3000 was just introduced right before the war started, but since it was so new they could not distribute it to all vaults, like the GECK. The ones in the vaults would have been well maintained so its perfectly plausible that a few survived, they just are rare. At least that is how i think it was explained in fallout 3.

Yeah, the PipBoy 3000 isn't a post-war invention. It was definitely released prior to the war, and there's significant evidence that the 2000 model was intended to be old and outdated in Fallout 2, if I remember correctly, though I don't remember any references in F1 that would indicate that. Besides, the versions in F1 and F2 were also attached to the player's arm, though they were bulkier than the 3000 model.

Well it was in FO1 and FO2 was 80 years later.
This I don't see. The pipboy seems to be a http://noscope.com/photostream/albums/various/pipboy.jpg, and http://i271.photobucket.com/albums/jj125/Gizmojunk/scr00043.gif on anyone in Fallout 1 or 2 (though it does appear on the arm in Van Buren).

[See those vacuum tubes behind the diamond wire mesh? That would be on someone's wrist? Those tubes (if they are small), make the screen to be about 8" diagonal at a guess. ]

You know what my manual of Fallout says? The one from the first, in its slightly battered shape? Right here, page 60: "The RobCo PIPBoy 2000 (hereafter called the PIPBoy), is a handy device that you wear on your wrist."
I completely forgot about that, and nobody seems to look in those faraway places like, by all that is holy on Olympus, manuals to the games they discuss. ^_^

Even if it is a PDA, it's wrist-mounted. And a cuff-like construction would be nice to fit it in.

My manual got destroyed in the hurricane, but I must have the PDF copy somewhere... That does not disprove what I've posted above. Manuals can be mistaken.

**Edit Here it is.
http://i271.photobucket.com/albums/jj125/Gizmojunk/page60.gif
and it does say just that (along with a size joke).
Still... It does not appear on anyone in the games (nor even on the http://i271.photobucket.com/albums/jj125/Gizmojunk/Vault_Suit.jpg close up in the ending), and it looks pretty much like that fan render I'd say...
and when you consider that those holo tapes plug into it... then it really seems (to me) to have been a mistake of some kind.

Sure, it's not shown, but that falls strictly under the restrictions of the engine. There was only one model for lads and lasses respectively wearing each and any kind of armour. To create separate ones for such a minor detail... ^_^
Long story short: There are so many differences between lore and actually shown content, it's the only thing that you can actually go by.

Those were 3d lightwave models that look to be on par with the ones FO3 has (meaning the heads :angel:). There was likely no limitation for 2d tile art that would stop the pipboy from being present if they wanted it. Modders have made their own sprite sets since. I don't think it was meant as anything but a menu at first. The art does not appear (to me) as something small enough for an arm ~The screen looks to be at least 8" across the diagonal.

Will FNV have exactly the same Pip Boy as in FO3?

Yes and no. It appears you're starting out with the Pipboy 3000 A model (The same kind The Lone Wanderer has) and there is supposedly a Pip Boy 3 billion, but I dont really think this is legitimate. (But it might, so dont nag me if it is indeed in the game)