Steve,
I'm not sure when the change took place but the YYYYdbase.csv is not created with the newer versions of VWS. How I handle the 50000 records overflow is never let it get that high. On Jan 1 each year I make a copy of the dbase.csv file, name it YYYYdbase.csv, and then I close VWS and with CSVEd I remove all the previous year's records from dbase.csv, restart VWS and your database is resized. I can't tell you what happens if you go over the magical 50000 records. It has never happened to me. I then have a copy of each year's database.
Hope this helps,
Jay