eBay is always changing and things that worked in the past can stop working at any time. It's the unfortunate thing about stealth.
VCCs can be reused but it's really rare, I doubt that was it. Listing too many auctions could lead to a MC999 where they ask you to call in to talk about your selling practices, but they won't outright indefinitely suspend you unless you were linked to a banned account.
Really, VPNs are one of the worst way to run stealth accounts. Lesser known ones can work, but they also can just as easily be shut down. And they cause more problems than what they're worth in my opinion. Were you using separate user accounts for each stealth? Maybe you accidentally logged into an account with an IP for a different stealth.
But either way, you rarely get suspended just for using an IP that was used with a suspended account (it would have to be an often abused IP, like common public proxies/WiFi. VPNs too, but since you said it's not a popular one then that's probably not the case unless it just happens to be used by a lot of stealthers). IP addresses are often recycled so chances are pretty much everyone has used an IP that was linked to a banned account. However if you do happen to use a banned IP, eBay will look deeply into your account and if anything else seems suspicious, that is where the suspension happens.
What I'm saying is that yes it's most likely the IP that got eBay suspicious of you, but other part(s) of your account lead up to the suspension as well so you'll have to figure out what else lead to the linking and eventual suspension of your account. Since you're weary of the VCC, how about trying a different one? Also, is there anything else you can think of that would make you stand out to eBay? Also you said your listings weren't branded, but they still could be high risk. For example, even non-branded cellphone cases can cause troubles on a new account.