I have... across a mainframe / oracle / mssql boundry. It was not exactly the most fun thing in the world I've ever done, though I am reticent to admit (btw, I don't like java on a "personal preference" level), using Java did make it considerably easier. The mainframe vendor (IBM) already had a great many objects we could use to interface with MQ and CICS... Oracle behaved in an intelligent manner (they have too much invested in java to not at least *attempt* to behave in an intelligent manner), and the MSSQL work... actually, now that I think about it, someone else completely did that work :)
i'm not saying that it's not likely and possible that if such a framework and series of libraries existed for perl, it wouldn't be equally suited. i just *personally* have no experience with perl on that level, nor have I successfully in my googling found a vendor (or preferably vendors) that provide a perl framework with such functionality. *sigh*, what a shame.