We are just other users like yourelf. There is no point in asking us abut having a new search option added.
You could contact eBay to suggest this, but it would probably be a wast of time. eBay does not accept suggestions from users.
If considering buying a motorhome here, do please be aware that motorhomes are for some reason one of the most common subject of fraudulent listings. It's important to understand that there is NO BUYER PROTECTION WHATSOEVER for motor vehicles bought here, however you pay and whether by auction or by classified ad.
The result is that eBay motors is a magnet for criminals. In a TV programme about organised crime, a senior police officer reported that one criminal gang alone had registered "multiple hundreds" of fake accounts on eBay to place fraudulent listings for non-existent motor vehicles.
"Selling" a vehicle here can be as simple as copying a picture of it and claiming to be selling it. Many buyers have been conned into paying for non-existent vehicles, so don't fall for excuses why it isn't available for inspection or for assurances that eBay will hold your payment safe until you have approved the vehicle. They won't! eBay will not help in any way. (eBay warns buyers in the user agreement that they do not guarantee that items for sale here will even exist!)
Even good feedback means nothing - hacked accounts are often used to place fraudulent ads for motor vehicles.
The golden rule is not to pay anything, not even a deposit, until you have seen and inspected the vehicle, checked the paperwork and had an HPI check. Then pay in cash, which is the only method of payment that is safe for both buyer and seller. Or take advice from your bank about safe methods of payment.
If a seller comes up with excuses not to accept these conditions, walk away from it.