I'm going to buy a new tramp and noticed ones for sale with and without the center beam. Can this safely be removed permanently? Does it not have structural significance? Also do I relocate the attachments for the wire that the gib blocks attach to to below to take advantage of these style tramps? (i.e. 
Gray
77' Nacra 5.2
Yes it can be removed. You MUST rivet the straps to the crossbeams though. I actuaally really liked having the beam there. That beam saved me a few times. Big puff hits and you dont have a good footing...Rather than sliding off the tramp on the leeward side, the crossbar would save me.
The bar keeps the crossbars from twisting....Rivets through the straps into the beam kinda solves that problem.
P19 & P19MX
TCDYC.com 10Mile Surfside,TX
Join us on Facebook: Surfside Sailing
if the new tramp has reinforced slits cut in it, for the jib block mount wires, you can move the mounting saddles for the wires below the tramp slot on the beams
the new holes will need to be as close to the tramp slot as possible or the old wires will be too short
alloy rivets won't be strong enough, use either money, stainless rivets or stainless bolts to mount the saddles
1982 nacra 5.2
2009 weta
If you remove the center cross piece and rivet the straps. Put the rivets at 10 O'colck and 2 O'clock in each strap (that will give you a total of 8 rivets in the front crossbar) and I agree, use stainless steel rivets. 3/16 should be fine.