I asked a dealer when we were shopping if the booth could be converted to table & chairs that wasn't technically available on a particular unit. He said he would ask Jayco if they would do it, supposedly they said it would cost an additional $1000 or $1500 (don't remember exactly). I'm quite confident I could build or buy-and-mod something for quite a bit less than that.
You could probably buy the parts pretty easy, but nbhybrid is right, the shipping alone will eat your lunch, along with the cost of installation if you're not going to do it yourself.
As an alternative, how about a hybrid design? Put a booth seat on one side of the table, and have the chairs on the other side? I'm not sure about how your floorplan might accommodate this, but it could be a workable solution...?
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!