Unfortunately, there's nothing else out there. I've emailed mark/space (the makers of the superb Missing Sync software for PPC - I used it extensively with my Axim) about supporting the blackberry, but they said they have no plans at this time. I recommend emailing them and letting them know you're interested. If enough people email, maybe they'll do it. They're great developers and very responsive. I own both TMS for Palm and PPC. Well worth the money.
Interestingly, when I emailed again asking about future support, the support person said "we'll add your request to the blackberry group". Makes me think there may be something going on.