Wow, what a bunch of hoops I had to jump through to ask this question. (And I ran it past customer service, too.)
I know about "spoofing" of numbers. (Hence the extra question mark in the subject line.) I know about the "7726" forwarding to report a spam text. But the phone that received the spam text is not a VZW phone. A reverse lookup on the number shows it to be a VZW number in Oklahoma. Looking at the reverse lookup site, I saw that I wasn't the only one to receive a spam text from that source today.
All I really want is to report the spam, and have someone check any logs that might show whether that number seems to be spewing texts to various area codes. If the number hasn't been spoofed, and someone looks into it further, I'm sure the spammer will claim they have an "opt-in" to send their [removed] . That would be a lie, but that's how spammers are. 
So if it really is a Verizon customer violating something in the Acceptable Use Policy/Terms of Service, maybe the account could be nuked? I'll be sending one of my usual reports to the FTC, for whatever good that might do, but meanwhile maybe there could be a mechanism for victims who aren't VZW customers to report spam messages. (I'm a customer, but not on the device that received the message. Next. I'll have to go see if there's a call history or some way to see if my VZW device has received any spam calls or texts. I'm pretty sure it's been on the Do Not Call Registry since I got it, but it's not a phone, so I won't be able to forward reports from that, either.)
Thanks for any help, and for an opportunity to vent. 
Profanity removed as required by Verizon Wireless Terms of Service
Message edited by Verizon Moderator.