There's a few cheaper ways of doing this, but if you have the motivation a blaster cabinet can be a great thing to have. I decided to build rather than buy so I could add a few things, and make sure it would be large enough to suit my needs. I just use a $15 husky siphon feed gun.
Here's a shot of the whole thing. Important points:
1. Trough like base to collect the media.
2. Slanted roof to make viewing easier.
3. Cut off sweat shirt sleeves stapled to the arm holes to keep keep media inside.
4. The windows get dusty, but don't really scratch. Glass is easier to wipe than plexi.
Added an attached water/oil separator. Wet air will clog the gun, and this also provides an easy point to connect your air hose on the outside of the cabinet.
This is a dirt bike air filter boot I happened to have. Conveniently it perfectly fits my shopvac. Hooking a shopvac to the cabinet during operation keeps dust from blowing and allows dust to settle faster when you are ready to open it up. If you're worried about your shop vac motor you can add some water to the bottom of the vac to help keep dust down. Mine has been fine, although the vac filter does need periodic cleaning.
Inside shot showing the dirt bike air filter. It's just a mesh screen, but it seems fine enough to block the media. As the media breaks down it turns to a finer dust and passes through the mesh. Also take a look at the edge where the door opens. I added a line of foam weather stripping all around to form a better seal when the door closes.
Here's the inside. Made a grate out of rebar and screening to set parts on. Also has a length of air hose permanently installed for easy setup. Also included a flourescent light inside the cabinet to increase visibility when the windows get dusty.
Before:
After: