I've finally succeeded in containing the chips and coolant flying off my BP clone. The containment consists of several pieces:
1) A telescoping way cover to protect the Y/Z ways behind the table. The cover extends from about 6-1/2" to 24", to cover the full range of motion of the table. The top is attached to the underside of the ram, while the bottom is attached to a 1/4" plate bolted to the back of the saddle. Both ends attach via piano hinges.
2) A Plexiglas enclosure around the front and sides of the table. This is 24" tall, and has a pair of bifold doors on the front, giving full access to the entire table when open.
3) A large sheet-metal tray under the table, to catch chips and coolant. This is roughly 3 feet deep, and 8 feet long. I had it fabricated by a local HVAC shop using galvanized steel sheet. It is mostly just folded from a single sheet, with the few seams spot-welded and soldered, to make them water-tight.
4) A pair of clear shower curtains, to catch the chips/coolant that escape between the telescoping way cover and the table enclosure.
I used it today for the first time, and it worked perfectly. After a full day of milling, I had piles of chips, but the only chips that reached the floor were a few strays that fell out when I opened the doors on the front of the table enclosure to do tool changes, etc.