Topeka, KS
Quoted from toyotaboy:I say we go with flat. I'm imagining at least 3 bad scenarios:
1. Someone pulls off one of the glass to retrieve a stuck ball, cuts them-self on the sharp corner
2. Someone leans on the unsupported middle, breaks at least one sheet of glass and fills all 4 playfields with shards costing you time for cleanup, and at least $50 plus shipping for a new piece
3. Someone not only leans and breaks glass, but puts hand into center, breaks the center bowl, and cuts up their hand on the broken glass
I'll design some sort of frame for the middle piece that can attach to the cabinets. The playfields can remain 45 degrees, nothing bad is likely to happen to a playfield.
Made a few tweaks to future pinball, latest download (left click link, then hit download button in upper right corner, do not save link as):
https://www.dropbox.com/s/4jnefp50ezfrfsw/lionman_1.1.fpt
lionman_v1.1_(resized).jpg
How big is the center area? If you use 1/4" plate glass with polished edges and have it tempered you should be fine. If anything should happen, the worst thing would be cleaning up all the little shards of glass! Any glass company should be able to help you out, If you were in Topeka, KS I would be glad to help with the glass! Yes, I work for a glass company. 
