newbie: need a cross-compiling environment with mesa

Hi,

for testing purposes I need a cross compiling environment (architecture 
doesn't really matter, it should be != x86) which has the mesa libs. I saw T2 
at Cebit and so I thought I'd try to do this with T2.

I tried several things last week but didn't get so far to get something with 
mesa built.

I'd like to have 
-a basic system
-some graphic libs (jpeg, png, jasper)
-mesa

X and desktop are not required.

I got quite far with "Generic System" for PowerPC, the base system 
built, "mine" failed (because of including something from /usr/include) but I 
didn't find mesa. Build-Pkg mesa started to work, but failed because there 
was no X. I didn't find a way to build X.

My other attempts didn't get so far. The Dreamcast target failed because in 
the generated kernel some numeric value didn't match with the expected value, 
for some other targets I got an assertion in bash, malloc.c.

This is on kubuntu 6.10 Edgy Eft.

So which target should I chose ? Generic, Exact Desktop or something else ? 
For which processor: PPC, Sparc, ARM ? 
If the base system builds, how can I build mesa after that ?
I don't need an installation CD or iso, I just need the environment installed 
on my machine so I can link to it when cross compiling.

Thanks for any hints
Alex