Yes crusinon2,... I'm it. Would've thought the "US Service Technician & Moderator" was the dead giveaway.
The crosstalk issue,... a combination of playing technique and/or set-up.
It's usually good to have the set-up checked by a local guitar tech in your area,
who is authorized Line 6, and knows JTV's. Local, because climate will affect
"I know the PCB was moved to the backside of the block, but anything else?"--- No. If there was anything else, they haven't told me yet.
"Unless one really knows what they're doing, jury-rigging stuff that wasn't
designed to work together is at the very least a pain in the arse"--- Right you are. Seen my share of Frankenstein'ed JTV's. Not always pretty, which is why they come across my bench in the first place.