In the US they are registered by their chassis manufacturer.


Some examples:


A-Class


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http://www.rvadventures.biz/wp-content/uploads/2014/01/Adventurer010.jpg

6ESP377 (CA) on Carfax

Vehicle:2003 FORD MH STRIPPED CHASSIS
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http://cdn-9.psndealer.com/e2/dealersite/images/discountrvs/vp3207569_1_large.jpg

5JVB701 (CA) on Carfax

Vehicle:2004 WORKHORSE W22
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http://www.dreamfindersrv.com/RV/7707432/images/003.JPG

ABG3650 (WA) on Carfax


Vehicle:2010 FREIGHTLINER X LINE MOTORHOME
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http://www.usedrvs4u.com/images/DSCN4488.JPG

3RVD330 (CA) on Carfax


Vehicle:1995 FORD F530F SUPER DUTY
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http://www.usedrvs4u.com/images/DSCN4383.JPG

B813DS (UT ) on Carfax


Vehicle:1992 CHEVROLET P30
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B/C-Class

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http://i1.rvusa.com/wm/showimagerv.ashx?id=3270368&width=100&height=75&quality=6- 0&crop=auto&t=3

FBY 580 (VT) on Carfax

Vehicle:2010 FORD E450 SUPER DUTY
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http://i1.rvusa.com/wm/showimagerv.ashx?id=14412249&w=250&q=60&c=auto&t=3

BDM-1651 (TX) on Carfax

Vehicle:2000 FORD E450 SUPER DUTY
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http://i1.rvusa.com/wm/showimagerv.ashx?id=16011737&t=3

BLY-8553 (TX) on Carfax

Vehicle:2005 CHEVROLET C5500 C5U042
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http://imganuncios.mitula.net/2004_gulf_stream_ultra_supreme_conquest_9898301209- 9619702.jpg

5AJ5965 (MD) on Carfax

Vehicle:2003 FORD E450 SUPER DUTY
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http://www.usedrvs4u.com/images/82 Motorhome 010.JPG

323WRK (WA) on Carfax

Vehicle:1982 FORD E350
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http://www.usedrvs4u.com/images/98 Tioga MH 002.JPG

913ZDV (WA) on Carfax

Vehicle:1998 FORD E SUPER DUTY RV
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