Having a root around RDG site and I came across a Myford 9" t-slotted face plate for very reasonable money. In fact, with my 5% discount card it only came to just over 33 squid all in.
If you have a Myford, or as I do, a way to hold Myford fittings on both my mill and lathe, it is a bargain.
In a couple of seconds, I transformed my 6" RT to a 9" one.

The other bonus for me is that the 8mm clamping set that fits all my other t-slotted items, fits this one as well.
Bogs