It's a bit late for the OP but sharing for future searches...
Today I discovered that Wago make DIN Rail holders for various cable connectors. There's a catalogue here (or search 'type:pdf Wago Installation Connectors'):
For solid core cables (good for cat5/6/7/KNX) you can take blocks to connect 2, 3, 4, 5 & 8 wires together. Naturally you will need 8 of these for cat7 for example.
Pricing is good. Eg: 1 x Wago 2273-500 + 8 x Wago 2273-202 (good enough to terminate the 8 wires in cat7 and then connect to one patch into your cabinet) works out at under 3EUR an 8 core cable. This is at least 4x cheaper than the Weidmuller mounts.
For stranded cable cores you would need to take the Wago 221 or 222 splicing connectors. Eg for an RGBW cable (5 core) you could use: Wago 221-500 + 5 x Wago 221-412. I can find this solution at close to 2EUR for the 5 cores.
Oh, they even do DIN mounts for KNX terminal blocks if you are that way inclined (Wago 243-112 or Wago 243-113).
HTH,
Robin