[Typo3] template design question

[Thomas Bolioli]

I am new to typo3 and invariably with my luck, the first site I need to 
do is a complex one designed completely by a graphic artist. Rhyme and 
reason took a vacation on this one. There are pages with one to three 
column main sections, different color top banners, etc and the nav is 
completely disconnected from a nice, structured hierarchy. The only good 
thing is that most of the site template i common. Think a three cell 
table (header, main and footer) where the main cell is then broken into 
1-3 cells and the changing colors all effect images and table 
backgrounds. My questions:

Is there a way to hard code (as opposed to HMENU) nav into the template 
while preserving the ability for urls to still be constructed via typo3? 
ie; java's c:url.

Is there a way to "echo" back typoscript variables into the html? I want 
to fix the changing color thing by using a variable in the page setup 
and have it used in the construction of urls, class names, etc; I looked 
through the ref and nothing seemed to scream out at me.

Is there a way to have a template within a template? I want to have a 
template that applies site wide while then having a secondary template 
that embed inside the main cell of the first. I looked at ext templates 
but I am not sure what they are and how they fit in. Any pointers to 
docs (or alternative ideas) for that would be appreciated.