If you didn't take 1Z0-047 for your current certification, you can take it and get the "Oracle Database SQL Expert" certification
If you use Application Express, you might take 1Z0-450 for the "Oracle Application Express Developer Certified Expert" certification
If you use Oracle Forms, you might take 1Z0-141 to get the "Oracle PL/SQL and Oracle Forms Developer" certification.
If you want to broaden your track, you can take 1Z0-052 and get the "Oracle Database 11g Administrator Certified Associate" certification.
1z0-141 or 1z0-151/1z1-151 relates to Forms OCP;
IMHO It's worth noting the Tuning exam is orientated towards Database Tuning from a DBA's viewpoint and not a developers viewpoint.
This is perhaps better illustrated by the training course recommended for this exam:
Oracle Database 11g: Performance Tuning DBA Release 2
As opposed to say the topics in the Oracle Database 11g: SQL Tuning Workshop Release 2 training course (which has no associated certification, certainly at present), which is typically more relevant for developers