Transcode x264 quality issue

Hi!

Maybe I have asome bad comprehension so please excuse my lack of knowledge if 
it appears that the problem comes from it.
I try to do a conversion of a movie in Quicktime PNG/alac codec using 
transcode 1.1.2 to a Quicktime h264/AAC one using the mov export module with 
the x264 and faac options. libx264 is a git version a less than a month old.
The goal is to have near perfect quality, whatever the size of the output 
file.
It works perfectly well but whatever the bitrate settings I provide ("-w 
10000", "-w 25000 --video_max_bitrate 25000", etc.), it seems stuck to a 8000 
output and yields a file with the exact same amount of octets, even using one 
path or two.
I use the following settings in my x264.cfg file, which should be max quality 
according to a documenbt on the mplayer site providing info on encoding x264, 
document I cannot find anymore and that's too bad :

subq = 6
analyse = all
8x8dct
me = 2
frameref = 5
bframes = 4
b_pyramid
weight_b
chroma_me
qcomp = 1.0
level_idc = 41
threads = 4
direct_pred = 3
threads = 4

The thing is : there are still some part of the film where I see some 
blockiness, some moving block where the image should be still.
I would have expected, a bit like the JPEG image file, to see the blockiness 
disappear when you ask for max quality.
I guess that if the quality (and even the number of bytes of the output) 
doesn't change after I increase the bitrate, it must be because it's not 
possible with my current settings to get any better.
Has anyone a suggestion that could improve my output?

Best regards,

	Richard Van Den Boom