I've tested the following devices myself:
Atomic Aquatics Cobalt
Oceanic Atom 3
Oceanic VT4
Suunto D9
All work fine. Feel free to post if you've tried something and it works so others know, and also if you're having any Lion-specific issues (please don't clog this up with general support requests for anything not related *specifically* to Lion, especially devices - post a new thread).
The next patch is looking good. Couple of people are testing it and I hope to have it out in the next few weeks.
As for the future, please be aware that I may drop Leopard support shortly. It's no longer supported for development (on Lion), and the number of users running it is a very small percentage. For now I'll maintain it, but as it gets more difficult to fight the future I'll drop it. PPC support will also be dropped, beginning with the next patch. Almost none of the existing MacDive user base is running on PPC machines (less than 10 people), and I don't have the capacity to keep supporting it. You'll still be able to use existing versions, just not new ones. Apologies, but it's becoming more and more difficult to support.
I'm aware that some things don't look quite right with the interface changes to Lion - I'll get on it

Cheers!