The last time I was shopping for a new trailer, a local dealer offered to replace the table and chairs with a U-Dinette. I agree the dinette is less comfortable than a table and chairs but we need the extra sleeping accommodations. So, I'd try a local RV dealer to see what they can offer.
Alternatively, you can buy a regular pedestal style residential set and modify the base so you can secure it to the floor. Check a few RVs at a local dealer to see how they secure the chairs.
2011 Rockwood Signature Ultra Lite 8293SS, 12K Equal-i-zer
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73
2010 Rockwood Roo 23SS (2012 - 2014)
2009 Ford F-150 XLT SuperCrew, 5.4L, 4x4, 5'6" bed (2012 - 2016)