So - upon reviewing a few threads I am aware you are able to import more tilesets, or overwrite what you have, (E is empty for that reason I'm assuming), so I thought to myself, "Well - if I can have XP tilesets in VX, might as well get the All Tile Set to put on page E so I can have a lot of choices"... but the Alltileset as most of you may know, is tiny when you view the PNG file, but once imported its normal size (in XP), but in VX, it's still really friggin' tiny - and I suppose my question is, how can I get the All tile set from XP to work in VX at their normal size?

The tilesets in RMVX have a very limited tileset size, whereas RMXP's tileset size is unlimited. And yes, TileE was left empty to allow you to add custom tiles. Even if this XP tileset was full-sized in the editor, you will not be able to use the whole thing. You will have to split the tileset up with any image editing software of your choice and import them as TileB, C, D, and/or E. Chances are, you won't have enough room unless you do some heavy modification to fit some of the tiles into TileA. VX's tilesets are very, very limited, and meant to be universal - and small.
So, it'll take a lot of effort to fit most of the RMXP tilesets into RMVX.

I can't remember which forum it's located under, but isn't there one specifically for xp to vx graphics?

I think someone already went out and imported the tilesets.

Check the resources thread