Marlin has made a couple of versions with 18.5" barrels in stainless and blued, regular and laminated stocks. Search the Gunsamerica website for "35 Rem" and you should be able to see some examples, like this one:
Absolutely, you can shorten barrels -- magazines as well. Not a complex task in the hands of a competent smith. I have seen several that look great, and are formed to the specs of the buyer. Not a bad idea.