Rack-mounted guitar signal splitter?

Nah it's just for splitting so I can have DI and amp input, and a third for... whatever, just for blending two amps and a DI or something. I mean I can get by with an a/b/y but I just wanted to see if there was a rackmount version. I just prefer rackmount stuff! Tidier.
 
Maybe try a buffer pedal. Passive guitar splitting could cause some some tone suck. Buffers convert high impedance to low to drive long cables and usually have isolated split outputs.

Google didn't find me too many, and the guy that made mine when out of business (Axess). I would try this one. Click on Pricing scroll down to Dual Buffer

http://www.vertexeffects.com/

They mostly seem to be made by custom rig builders like Pete Cornish or Dave Friedman. The Huge Racks forum may be a good place to research.
 
First Google result for "guitar signal splitter"; £18.83 - dunno about the quality tho, and it's not rack mounted either

http://www.mveducation.com/invt/61420/

I got the name from fifth result, after googling a bit more I found this; costs whopping £458.64 for the passive and 589.18 for the active tho. He also does custom jobs, so you could get it as rackmounted too.

http://www.petecornish.co.uk/SAEABCBox.html
http://www.petecornish.co.uk/SAEAC3waysplitmute.html

Edit: Morley ABC

http://www.thomann.de/gb/morley_abc.htm

Palmer PGA01

http://www.thomann.de/gb/palmer_pga01_triline_guitar_router.htm

Then there is also this:

Guitar -> DI -> Splitter