Snowaydude: you have several options for a rappel device.
However, safe rappelling is mainly about learning good habits, not using a magical piece of equipment. You should never (never!) let go the braking side of the rope, unless you are secure (locked off, clipped in, whatever). I'm sure you understand this in theory, but maybe it's not "in your blood" yet. Maybe you haven't practised enough.
Your Verso belay device is a poor choice for typical caving. It is tricky to lock off; it could be dropped at rebelays or pitch heads; it has relatively low friction on single rope (especially thin rope); and rapid wear from gritty caving rope could compromise its integrity. I'm not saying you should
never use it for caving -- just recognise that it will only be suitable in a narrow range of circumstances. In practice, you're better off with a caving descender -- most likely a bobbin or a rack.
The
Petzl Stop is the most common auto-locking caving descender (and the main descender used here in the UK). It is a much better descender than your Verso, but the auto-lock has the same panic-grab problem as your Bachmann hitch. It is better to think of the auto-lock as a
convenience feature, not a safety feature.
If you
really want a fail-safe rappel backup, you could use a double-brake descender -- such as the
Kong Indy,
Anthron Double Stop, or
SRTE Double Stop [PDF]. These are immune to the panic-grab reaction, but they are correspondingly bulkier, heavier, and more fiddly to use than a simple descender.
For the ultimate in rappel safety (or paranoia
), get yourself a
Petzl ASAP, as used in industrial rope access. It is effectively a modern, mechanical version of a knot backup -- but unlike your Bachmann hitch, it's completely reliable. It's also expensive, heavy, and bulky.
I use a
Petzl Simple, which is the most common descender in Europe. It is normally used without any rappel backup. It has proved sufficiently safe when used correctly, because we don't have a trail of dead bodies leading back to it.
The same can be said of using racks without a backup.
Summary: it
is possible to fix the problem with magical equipment, but this equipment can be annoying or impractical for caving. Most cavers fix the problem using technique and training instead, so that they can be safe using a simple descender (such as a rack or bobbin).