I have been dealing with apache based reverse proxies for some time now and I have come to conclusion that application code will always have absolute links (ex. http://internal.servera.com/image.jpg or /image.jpg) and break the proxies.  I am tired of having to argue with the code issues. So I am looking into outputfilters to help me with this. 
 
I have looked into the following outputfilters:
mod_sar  
mod_proxy_html
mod_ext_filter
mod_perl2/ModProxyPerlHtml
 
I am currently needing a commerical support solution and thus far only modules within the Apache distribution is supported.  I know mod_ext_filter is meets this requirement, however I can see this being a major performance bottleneck.
 
I hear some good things about mod_proxy_html but concerned with the dependency of the external library.  Also no commercial support(Covalent). 
 
Mod_sar does not have library dependencies, but again no commercial support, that I have found.
 
ModProxyPerlHtml, no commercial support and does not seem to be heavily used.
 
OK, my question to the list is what experiences and suggestions can you guys/gals give on this?  Also I have plans to use mod_deflate and mod_cache in conjunction so any issues? 
 
Your time and help is very much appreciated!