1) I could've sworn there was a plug-in available for making any instrument sound like a metal guitar...it didn't matter which instrument is was, it was automatically converted to a gritty, heavy metal guitar when the plug-in was loaded to the track. I saw this plug-in once, however, I cannot seem to find it. Anyone have any ideas?
 
2) In relation to SessionDrummer, I'm having trouble locating tambourines and hand claps. I have noticed that there are several layers of instrument folders in the SessionDrummer folder that look too cumbersome to wade through. And Media Player doesn't support those formats for sampling them. Where can I find tambourines and hand claps?

Sometimes I use Windows to search for samples. In this case looking specifically in Session Drummer\Content\Kits (where ever it is installed) will narrow the search quite a bit. Claps and tambourines are not well represented in Session Drummer but the samples show up in a search. The sfz files containing the samples are one directory above the samples. I also using this type of search useful when searching large patch libraries like DimPro and Rapture.

I don't know about Session Drummer but TTS-1 has both handclaps and Tambourines.  Have you looked at them?

Are you sure you're not just thinking of Guitar Rig? Heh heh....

Are you talking about CamelCrusher?  I think they still offer it as a free download.
 
http://www.camelaudio.com/camelcrusher.php

Re 1. - You are probably thinking of Overloud TH2 (?), included with Sonar as an Audio FX.
 
Browser > Plugins > Audio FX
Drag to track FX bin.

1) I could've sworn there was a plug-in available for making any instrument sound like a metal guitar...it didn't matter which instrument is was, it was automatically converted to a gritty, heavy metal guitar when the plug-in was loaded to the track.

I do not think so. You are probably thinking about an Amp Simulator. But these just add distortion and other things. It will not make any instruemtn sound like a "Metal Guitar." 
 
A trumpet, viola, flute, drums, vocals and every other different kind of instrument will not sound like a "Metal Guitar" when you add an Amp sim to it. It will just sound like a trumpet, viola, flute, drums & vocals that is distorted or/and what ever other effect you add to it that the amp sim offers.
 
CJ