There are many of us who never considered ACS 4.2 production-quality software, frankly. That's one reason for our labelling our current work an "alpha" release.
Also, we're working on an RDBMS-independent search package (that obviously has to interface with RDBMS-dependent things like InterMedia) and until both Oracle and Postgres support that fully I'm hesitant to label our release "beta". This is my next, personal upcoming task.
However you can still use the ACS 4.2 site-wide-search package with the Oracle version, and it's still included along with the deprecated acs-interface so folks will have a working solution in the short-term.
Your timeframe is very tight, so I do understand your being a bit queasy about OpenACS 4. The OpenACS 4 framework will support ACS 4.2 packages, however, so you would have that as a fallback if one or more of our versions were to introduce errors.
