I'm looking for a detailed split in the number of companies in the US
(nationwide) based on revenues generated. Answer needs to have a
reputable source and data as new as possible.

I'm not exactly sure what you're searching for, but the economic
census lists indsutries by revenue and number of companies.  I
downloaded this in XLS format.
http://factfinder.census.gov/servlet/IBQTable?_bm=y&-filter=&-sortkey2=&-sortkey1=-ESTAB&-defOrder=Y&-ds_name=EC0200A1&-sortkey0=-RCPTOT&-geo_id=01000US&-dataitem=GEO_ID$|NAICS2002|NAICS2002$|OPTAX$|FOOTID|YEAR|ESTAB|RCPTOT|PAYANT|EMP&-_lang=en&-fds_name=EC0200A1

Looking at publicly traded companies we can find the following breakdown:
(source: Yahoo! Finance)
Revenue: 

$100 billion +: 13 companies
$50-100 billion: 43 companies
$25-50 billion: 79 companies
$10-25 billion: 215 companies
$5-10 billion: 238 companies
$1-5 billion: 959 companies
$500 million - 1 billion: 589 companies
$250 million -$500 million: 670 companies
$100-250 million: 895 companies
$10-100 million: 2331 companies
$0-10 million: 1625 companies

I'm actually looking for the "yahoo like" numbers but for the whole
economy, including the non-listed companies.