I agree with Robin about downsizing, where we differ is on what.
Ebay your VX-2100, they're currently selling for $1700-1800 and buy an HDV camcorder. As good as the footage from your VX-2100 is, (I've shot several VX series cameras in the last decade) HDV is just better at 1080I.
Your VX is a 3-chip CCD so downsizing to a single chip Mini-DV model might be a little disappointing in the picture quality - so I'd go HDV. Got an HDTV? footage straight from the camera is stunning!!!.
The problem with trying to house your camera for diving/snorkeling is that any of the housings you listed will be larger and heavy.
Mechanical housings run bigger since they need room (airspace) for the linkages so then you need more weight to compensate. My buddy has an older TRV series MiniDV camera in an Ikelite clear/red tube housing like the one for your VX-2100, it's heavy and bulky - must be 20lbs. or more. My Amphibico EVO by comparison - an all Aluminum housing - weighs 10lbs. Of course my housing cost around $2500.
For $1930 you can buy a Canon HV20 single chip HDV camera in an Ikelite housing from B&H. Or $1675 for the HV20 with an Equinox ProPak 6 housing. Read the review at camcorderinfo.com.
$1459 buys the Sony HDR-HC5 in an Equinox housing. Also consider getting the bigger sensor in the Sony HDR-HC7 in the Equinox housing for $1999. Although it has some low-light issues.
If I was doing a lot of snorkeling/freediving, I think I'd go all out and buy a
Seatools housing. They're machined but absolutely molded around the camcorder, you could almost put it in a big BC pocket. They're more money at around $2500-2700 but are only 3lbs. and a tiny 7x7x4". They make one for the Canon HV10, the Sony HC series and some of the Sony SR series HDV camcorders. But then you're still looking at another $1000-1400 for the camera.
The Ikelite for the Sony HC7 at 9lbs. is 1/2 the size/weight of the housing for yours -
H20Photopros sells the housing for $1250. It's the newer design Ikelite housing built around a 4" square tube instead of the round one your VX-2100 requires.
The ewa bags and the Epic housing are just weather protectors - designed for surf and kayak filming. I wouldn't trust my $2K camera to either one - and they don't have the depth rating to be useful. Even Epic says so:
Epic Camera Housings are designed primarily for use in or near the water. They are recommended for snorkeling, surfing, boating, shallow dives, and any other situation where you camera could come in contact with water.
hth,