I've got the first iteration of the Smallrig GH5 Cage. I also have a top handle, a baseplate with railblocks, and a nato rail for the handle. It's a complete system I used as my starter kit, but moved on to a Zacuto system. Otherwise, it was a great kit. Here are smallrig's product numbers with original retail price:
$89 -- SMALLRIG DSLR Cage for PANASONIC Lumix GH5 1965
$92 -- SMALLRIG 15mm Rail Support System Baseplate 1841
$48 -- SMALLRIG Camera / Camcorder Action Stabilizing NATO Handle 1955
$14 -- SMALLRIG Quick Release Safety Rail(46mm) 1409
Cost $243 new, would let it all go for $165 plus PP fees S/H.
I also have 15mm rails (carbon fiber and aluminum) plus an HDMI clamp for the cage, if interested.