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Is an eccentric bb a better option than a chain tensioner?
I think that's open to debate. I've run both and I find the chain tensioner much simpler to use and maintain, especially as the EBB I had requires you to remove the nds crank to tension the chain. I do plan to get a better quality EBB and try again at some point over the summer. Some people claim that a chain tensioner isn't up to handling the torque you generate in cross, but I've never had that problem.
Any better options in steel?
A Pompino is the obvious choice. My first SSCX bike was one, and I enjoyed riding it off road a lot. The mud clearance wasn't great, but it was one of the earlier versions and On-One have improved that since. There does seem to be a lot more choice for specific SSCX steel frames though, i.e. All-City, Traitor, Genesis, Kona et al.
Probably, there's not a lot of choice to be honest. You occasionally find a Felt Breed come up on ebay and the odd Cinelli Mash but that's it.
Are you set on a specific SSCX frame? It's a lot easier to pick up a cheap geared cross frame, like @Chalfie 's CAADX with a BB30 and use an eccentric bottom bracket, to turn it into an SSCX bike. My frame is BB30 but I use a tensioner and it works well for me.