Hello Markus,
This is an interesting idea but unfortunately SmartInspect currently doesn't support such a behavior. Here's why: After a TSiLogEntry object has been logged and the event handler for the OnLogEntry event has been called, the TSiLogEntry object's memory is freed. This means that any references to this object are no longer valid. So, if you try to store some log entries in the OnLogEntry or OnFilter events for later use, you would run into problems when trying to access them later.
If you are concerned about the size of a log, you might want to take a look at the "maxsize" option of the file protocol. With the maxsize option, you can set a size limit for a log file. When using this option, you don't need to worry about your log file size but still can have more than enough information to analyze possible errors. Here's an example of a connections string with the maxsize option specified:
Si.Connections := 'file(filename=log.sil, maxsize=1024)';
The maxsize value is interpreted as KB, so that the above connections string would result in a log file named "log.sil" with a maximum size of 1MB. Hope this helps!