If crosstalk on CAT5 cables can't be avoided in a noisy environment, one option is to use a shielding cable and grounding one side to allow the noise to bleed off. I had to do this for an auto paint shop bay where they had lots of lighting, air compressors, fans, etc..
And no I don't install cabling it's actually a pain to do so but my buddies always come up with crazy ideas and I go with the flow and help them.
