Does any one know where I could possibly find solid Wii tech specs, particularly with respect to fragment shader support (or 'fragment shader effects' supported in hardware) and ANY (if there is any) support for vertex shading?

Not sure if the specific specs are out there...console specs are hard to get...not sure why...can't an informed person just look at the chips and figure it out?

Indeed, very little information at all is floating around out there (particularly for what I am looking for.) All you get are quotes like "Yes wii can do normal mapping."

I am sure there is some confidentiality agreements keeping devs from talking, but you think there would be some patent applications, or independant investigations that could produce more answers...

http://en.wikipedia.org/wiki/Nintendo_Wii#Technical_specifications

This should be pretty accurate coming from Wiki.

If you have $2500 you can buy a Wii dev kit and tell us all what you find.  :)  Seriously though, if the information were out there, fanboys would be all over it like... eh, you fill in the blank.  The point is, it wouldn't stay secret long.

I honestly think that Nintendo is kinda shooting themselves in the foot by not releasing the specs.  They don't want people to compare the specs to the RSX or Xenos, but it's no secret that the Wii is no graphics powerhouse.  People are going to compare them based on conjecture and speculation without the specs, you might as well put the numbers out there and let everyone see in black and white exactly what improvements have been made over the Gamecube.

Since you asked specifically about fragment shader support, in order to understand that, it really helps to define what a fragment shader is.  It's really nothing more than a series of mathematical operations on various inputs, most of which are textures, and the output is a fragment.  The differences between various GPU architectures define which operations can be performed, how many in one rendering pass, what kind of inputs and data types are available (integer, floating point, etc.), and so on.  Even the GeForce 2 had "shaders", they just weren't called that before DirectX 8.0.  Whenever someone tells you the Wii does support shaders or doesn't support shaders, ask what kind of shaders they're talking about.  I think it's pretty obvious that the Wii supports at least GeForce-2-level "shaders" but not something as advanced as, say, Shader Model 3.0.

As far as I know there isn't any confirmed specs, just the specs IGN revealed from devs before the Wii launched that are used by Wikipedia. I've heard it was revealed by leaked/misplaced technical document that the TEV count was increased from 4 to 8 but I don't know where that was.

I understand why Nintendo didn't reveal the specs prior to launch since the didn't want the same thing to happen to the Wii as happend to the DS (when the PSP's hype got doubled because it was 333MHz vs 66MHz).  I agree though there's not reason not to release them now seeing as they're out in the open.

http://forum.beyond3d.com/showthread.php?t=1086

That very old thread discusses the Flipper's shaders (starts about 4 posts down), basically they're older pre-DirectX GeForce 2 style.  Presumably Hollywood uses the same format.

http://www.maxconsole.net/?newsid=8802

There are some detailed specs. I'm not sure how accurate they are, but whatever.

Well, according to that thread, they're actually more flexible than NV2X, which is a DirectX 8 part.  Fewer combiner ops, but the ability to do dependent texture fetches in the same rendering pass, and more stages in one pass.  It sounds closest to pixel shader 1.4.

The 729MHz figure is pure BULL***t because that was an early dev kit, the actual figure is 1.1 GHz for clock speed but I don't know about the 243 MHz figure...