OK so this Topic falls squarely between a Kit find and a Scratch build. This guy Machinator aparently posts on Bolter and Chainsword and another forum I can't remember. The basic concept is he's using his own resin tracks, which you can buy, and a forgeworld MkIIb kit.
I also found over at Apoc 4ok this
http://apocalypse40k.com/index.php?/top ... e-marines/
This is also a kit available from his ebay store.
So take a look at his Landaraider here:
http://apocalypse40k.com/index.php?/top ... k1or-mk15/
Hasta