Speeding up Blind SQL Injections using Conditional Errors in MySQL

Please note that this article expects some prior knowledge of blind SQL injections.

Edit: If you want to read about this in Russisn, its been published here in 2009.
Edit2: jrm` provided me with a working implementation of this method which he coded using information from this article. His code can be read at the bottom of this article or downloaded here.
Edit3: jrm` also created python script which can be downloaded here.

Usually a syntax error in a blind SQL injection will have some sort of visible effect in the output of a web application. So what if we could conditionally generate such an error instead of relying on conditionally delaying and timing a request using functions such as BENCHMARK or SLEEP?