I'm a Canon shooter, and while I've been using Nikon speedlites with RadioPopper JrX remotes for over a year now, I've decided to switch to Canon flashes. As a result, I'm selling my Nikon flashes, RadioPoppers, and modified Nikon hot shoes.
The AS-E900 hot shoes are modified to add 3.5mm TRS connectors (standard headphone cables), which allows remote power control from the RadioPoppers. Some have two jacks, some have one, and one has rather large connectors protruding from the sides (this was my first attempt). All of these are epoxied inside, which secures the solder joints, but prevents any further modification.
All prices are net to me, shipped USPS priority flat-rate to the lower 48, except as noted.
(1) RadioPopper JrX transmitter: $60 $50 $45 SOLD
(7) Nikon AS-E900 hot shoes, modified to use standard 3.5mm TRS connectors. $10 SOLD each. Due to the cost of shipping, you'll need to buy at least 3 of these, or buy them with the transmitter.. Alternatively, you can buy just one or two, and pay your own shipping.
Full disclosure on the JrX transmitter: occasionally, it will stop transmitting. Removing the battery for a second or two and putting it back in has always fixed it. It only seems to happen when it's been sitting unused for a few weeks - never in the middle of a session (though of course I can't guarantee that). Additionally, one of the two screws that holds the metal plate on the bottom came out at some point, and got lost. I replaced it with a similar screw from the local hardware store, and haven't had any issues. Note that the "not transmitting" issue predates the screw falling out. Additionally, one of the power dials on the transmitter comes off more easily than it should. A drop of super glue would fix it easily.
I'd prefer to sell the remainder all at once, if possible. If you want to take the transmitter and hot shoes, I'll sell the whole lot for SOLD.. Payment by PayPal preferred.