Just having a bit of a side-explore of the VXT75 transmission - basically a MTX75 with higher torque rating, and fitted to the FWD Diesel Transit Vans. I poked some chat up on Facebook but will copy it here...
The Duratec LF 2.0 in the XR4 is good for 190Nm. We know that the gearbox is a marginal thing in the XR4, so lets put the IB5+ boxes peak limit at around 200Nm. Which makes sense - there are documents showing that even the earlier 1.7 was a little over powered for the base IB5 - the IB5+ must be at least a little bit stronger given the application.
I then found a Ford document for the 4x4 version of the MTX75. That document lists the MTX75 as rated for 280Nm. So let's assume that the all have a similar rating. Here's the link (Page 9):
Ford Mondeo 4x4 MTX75 Technical Service Training
The 2.2 TDCi in the 2008 Transit is rated at 285Nm, although I see that the 2.2 TDCi Duratorq Puma can overboost to 310Nm. So we can easily assume that the VXT75 is rated to at least 310Nm, and probably higher. I thought I was on the money with this link below, but while it gives the Torque rating of the powerplants, it doesn't give the same for the transmissions.
Ford Powertrain Product Guide 2007
There's a 2.4 Duratorq TDCi Puma that is rated to 375Nm, but it looks like that is a RWD application with either the MT75 5 Spd or more likely the MT82 6 Spd.....
But all this looks like it pales in comparison to the MMT6. This non-official link quotes 450Nm for boxes built between 5/03 to 5/05 and 500Nm thereafter. I don't seem to be able to find any models that shipped to Australia with the MMT6 other than Focus ST models. It can be found on a whole heap of cars in Europe - MkIII Focus, C-Max,S-Max, Galaxy and both the MK3 and MkIV Mondeos. The MkIV Mondeo that hit Australia only came with some rare 5 Speed manuals - MTX's again. The only other hope might have been the Kuga, but since the Euro Kuga didn't come to replace the US Escape until 2012, the only 6 Speed Manual is on the Volvo Turbo engine and that's a different beast altogether.
Talkford Discussion on Torque Ratings
Lukeyson