I think it's a reasonable enough request - I've certainly had to 
process CSV files with comments. Iain - appologies for not looking at 
your request before now - 3 years is a pretty poor response time.

Some thoughts:
 * this should target 2.6, not 2.5 (as 2.5 is in maintenance only)?
 * the check that disallows "space" - I wonder what other things it 
should disallow - the delimiter?
 * should it support multicharacter comments, like the C++ //-style 
comment? I think no.
 * any implications for the py3k port?

Skip - are you happy making the changes, or should I dust off my 
working copy?