Databases do not limit SQL statements to 28672 characters, at least not since around version 9 of Oracle (and even in 8 it apparently wasn't enforced Ask Tom "maximum length of sql statement" ).
I'm not sure what the limit is in SAP6.0 or whether it is an SAP parameter, but I managed to blow it up by sending multiple selection-tables, one of which would break it with a few hundred rows, into a query against around fourteen different tables. As it happened it was a non-issue for us because they really wanted everything in that situation, so we just gave them that as an option.