I've just released a tool to filter BLAST result files with user-defined constraints.

BLAST Filter Tool (BFT) contains:

• the filtering engine to be used as a command-line tool a graphical
• filter editor to create filters in a very straightforward way without the need to use any obscure query language

BFT is available as an open-source project here: https://github.com/pgdurand/BLAST-Filter-Tool

Comments, feedbacks, contributions, use cases, etc. are welcome.