See if a local RV dealer has a spare air mattress sofa? I don't know the dimensions but when we were shopping for our latest TT, we had a couple dealers that were willing to swap out some furniture to make a sale.
This RVW video seems to show a 2015 23IKSS with a different style sofa.
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)