No its all to do with cc's here in Ireland. Age only comes into it if its deemed a classic or veteran at which stage cc does not matter, its a flat rate for limited mileage. Its similar for commercial, its a flat rate for all vehicles per weight band.
Thats why the vast majority of 4x4's in Ireland are commercial, low VRT and low road tax. They do a Range Rover Sport commercial here in Ireland, it costs about €50,000 as opposed to €90,000 in passenger form and for a TDV8 its about €150 per year as against €2,000 per year road tax.
Back to the original question, of putting a P38 body on a RRC chassis, I'd say no chance. As Devac said above, different wheelbase, its about 4 inches wider, a foot longer, completely different chassis shape (the RRC chassis rail is more or less straight from front to back but the P38 Chassis rails get wider under the body and narrower under the engine). Its not even related to the LSE, yes they developed the air suspension on the LSE but thats about it as far as relationship goes, the P38 was a completely different design.
You'd spend far more in time and effort than on say putting a soft dash RRc on an older chassis and I think the end result (if successful at all) would be a complete dog. Also remember the P38 has a chassis number behind the windscreen, you'll never get that past an inspector. If the road tax is a big issue why not commercialise it. There are quite a few Landcruiser amazons knocking about with just the boot paneled out, not the back seats, find out how they're doing that.
