To be honest, I think a 30" deserves way better than DisplayLink
I'd pick up a second MiniDisplayPort to dual-link DVI adapter and dual-link-capable KVM.
I can't - unless I want to be stuck on WiFi. Currently the second TB/MDP port is for my ethernet cable adapter.
Now if DisplayLink does support the 30" I'd run with that still. I'm just not going to do it if it won't support the 30".
As for KVM, I have two separate boxes. The first one supports the 24" Cinema Display because it's got the lower resolution. The second one supports two 30" Displays - which is why I got it. I'm just not using the second port in the back of that KVM because I have no way to attach it to the work MBP.
PS. For the record: Left side of 2015 work MBP> Power, 2xTB, 1 USB. Right side of MBP, 1 USB, 1 HDMI. That's all the ports this Mac has.