Can anyone tell me if there are after market mechanical hubs for newer style sidekicks?

What do you consider a "newer style" Sidekick?  Sidekicks were built between 1989 & 1998, if you're asking about after market free wheel hubs, all years take the same hubs.

As far as we understood they went to non mechanical hubs on the 89-90 sidekicks. Is this correct We don't have a suzuki but have been looking and would like one with  mechanical front hubs for towing. Our question is are there after market mechanical front hubs available if the one we purchase doesn't have them?  Thanks

When you say Mechanical, you mean Manuel (the ones you need to turn to lock) vs. Automatic hubs that are always locked?

Yes, there are options for manual locking hubs.  I never had a problem with flat towing my Sidekick when it had the "Auto Free Wheeling" hubs.  There are Mile Marker hubs available from many sources, you can even look on eBay and find some options, and sometimes even the early OEM Aisin hubs.