I am currently a dozen or so hours away from finishing up an isolated DMX repeater/splitter. The reason I want this is that I will be having between 12-16 lynx boxes on the roof, in the house, both sides of the driveway, and more in the further front of the yard. This will allow me to keep zones and thus simplify wiring and I don't have to think to hard how to chain the Lynx boxes.
Basic specifications are:
1. 5.0 Vdc (1 Amp) input - This would be from a small switched mode wall supply (like the one at sparkfun).
2. RJ45 input. While some people may cry for XLR5 (or 3), this is for DIY. I am also not intending this unit to be outside in the elements or for commercial use. It is intended to be right next to the Enttec box.
3. Five isolated outputs (1 input + 5 outputs = 6 socket plate) with RJ45 jacks. The reason for 5 is that the nice wall supply I found handles 5 outputs nicely and this also keeps 6 total jacks on the board making it square. Sorta like me.

4. Status indicators for power/comms.
5. Install as many channels as needed. Since the output stage is basically mirrored copied, you don't have to install all 5.
6. Estimated costs would be around $60 for parts, PCB, and enclosure in low volumes (like QTY 1). Might be as low as $40 in QTY's of 25 or so. This would be a through hole and SMT design to keep costs down. However, the SMT devices are fairly large pitch. If I would run a coop it would be billed out as PCB + Core & # of output channels.
NOTE: This just REPEATS the DMX signal. It is not a multi-universe module.