[woodnthings]

There are "standards" for 10" table saws.
Depth front to rear is typically 27"
Most side extensions will interchange on 10" saws, but may require some holes to be drilled.
Fence rails are either round (old Deltas),
rectangular 2 x 3" tubing, (Biesemeyer and clones)
or an extrusion for the Unifence head (newer but discontinued)
The length of the fence itself is typically longer than 27" front to rear.

There are very rare occasions where you would need to crosscut wider than 48"
This setting on my ultra wide 3 saw setup allows me to cut just a bit wider than 48", but I only did this as an example:

Shown on the lower right is the Delta Unifence head with an aftermarket extended length extrusion. The front rail is a different extrusion specific to the Unifence.

Shown below are the three Unifence heads (now all but extinct)I have collected from Ebay and purchased new. The blue one has a sacrifial wood fence for making rabbetts.

You might consider a router table extension which adds more width to the original table, and adds the router to save floor space.