Yes, you are correct in that truggy cvds are longer than buggy cvds, but I'm not talking about using truggy cvd's on a buggy. I'm talking about parts compatibility between a 7.5 buggy and the Lightning 2 series buggy that already can share many parts between them.

I was just using my truggy as an example of what fits between the HB Lightning series and the Kyosho 7.5 based RC's. The IGT is based on the 7.5, as is the Inferno ST RTR. The Lightning buggies, and the Lightning Stadium Pro truggies share tons of parts with the 7.5 based stuff. The toe plates, castor plates, hubs, and many front suspension parts. They aren't made by the same companies but the parts fit fine.

My entire LSP front end hub assembly was built from Topcad CNC stuff made for the Kyosho 7.5 buggy. You can see some pics here:
LSP Gallery

The very first picture is of Topcad 7.5 hubs, and steering knuckles with proline 23mm adapters. The cvd's are LST shafts, and sportwerks boots using the hotbodies cvd internals. With the rest of the pics you can see that it installed fine on the truck.