It's hard to stack pro gear with consumer boxes since the rack ears make the pro box 19", where all your other stuff is probably closer to 17" wide. Maybe put some black electrical tape over the rack ears so the xo looks narrower.
The rackmount ears come off the CX3400. You can cut some thin Aluminum sheet to size. Drill some holes. Paint them black. Then attach them to the unit. If you make a good job of it, it will look stock.Reposting to see if anything new has come up in the last three years. I got a new receive (LX-801) that has Bi-amp capability on the fronts, so I tried it and it's okay, but not as good as using a dedicated cross-over. So I'm looking to go back, but I'd really like to make my cross-over look like the rest of my system.