Any particular jets in mind?
There's a Canadian 3d Modeller http://www.milviz.com/ that makes some of the best detailed work I've seen. but they only have the Me 262.
they also sell all their models on TurboSquid although you can contact then directly to get other formats saved out - or even models comissioned.
One of their modellers has his own 3d artwork site - where some of his more unusual work is shown at http://www.airart3d.com/
Not sure if any is for sale though, His 3d Gallery part of the website has a Horten Ho18b , the odd Fw TreiFlugel, and in the "older" images
renderes of Ju EF.128, 132, 137, Messerschmitt Zerstörer I, Horten Ho 229B, Messerschmitt P.1110/I and other variants.
Other odd links you could try ( from his old site ) are:
I'm just throwing up what could be close, It can get quite expensive,
particularly the Milviz models as they are often the main source for MS Flight Simulator editions
but they do go into some of the best cockpit details available anywhere.
The other sources I have is commissioning models from http://www.perspectx.com/