Yeah, its hard to find 42" panels. Check your local market for 39/40/42" and cross reference with ebay or
to find the tcon. If the tcon is removeable (not glued to panel) and is on an innolux panel, it should be compatible.
Known-tested compatibility table:
42" SE42UM (must use seiki backlight driver, no scanning)
40" Lg 40ub8000
40" BDM4065 (must use philips backlight driver, no scanning)
39" SE39UY04
39" SE39UY04-1 (must use seiki backlight driver, no scanning)
28" U28H750 (quantum dot backlight)
28" UHD TN panel from any vendor
Others are untested but may work, send picture of tcon.