There isn't a limitation, but why on earth would you do it?  What are you trying to achieve?  This would be a performance killer.  Also, be aware your cursors will probably need to be static or else you'll end up stuck in the fetching loop.

Seriously though, cursors are bad.  I rewrote our MRP routine (cursor based) to a VB 6 application and the 50 minute routine now takes approximately 8 minutes.