Is there a difference between the meanings of these two sentences:1) The insinuation that he has been paid by somebody is ridiculous.
2) The insinuation that he has been paid by anybody is ridiculous.
Sentence (2) expressly has in mind more than one possible payer. I think that "anybody" needs to receive emphatic stress for (2) to be acceptable. The two sentences could actually be combined, with (2) amplifying the message of (1):
(3) The notion that he has been paid by somebody—anybody—is ridiculous.