I know this is a late reply but OBN will be starting production again as soon as his hunt season ends.
You may want to message him.
His appear to be pretty nice stuff, lathe turned etc.
I am modding an old headphone cap into a dual connector cap and will be posting a how-to pretty soon.
(Waiting on the PG7 thread tap right now)
Honestly though, if I had the time to wait, I would buy the one from OBN.
There is also a guy on ebay offering the dual end caps but his ebay rating is terrible at 64 percent.
I decided not to chance ordering from him after reading the more recent reviews regarding merchandise not received and bad communications.
The problem with modding a standard headphone end cap into a two plug end cap is the cost of the tap needed for the PG7 metric threads.
A 1/2 -20 NF tap might work since it is very close to the PG7, and because the nylon threads leave a tiny bit of room for error.
Oh, and a metric drill bit to go with the PG7 tap .........