Can anyone tell me where the cabin air filter is on a 2000 XJ8 VDP.

 

Did you find it, I'm looking too.

 

there is no cabin air filter

 

Yes there is ( I have it on my car) but it was a very rare option only available for a couple of years ( the 4 filters elements have been NLA since at least 2001.)
It's on the intake plenum, underneath the plastic trim piece at the base of the windshield

 

What are the dimensions of the filter(s)? Maybe there is an equivalent or near equivalent that would work.

 

No way, they are all differents with a molded plastic frame