RV values, by and large, drop like a rock the first few years.
The people who purachased our Jayco Eagle new in 2008 paid close to $27,000 (personally I think they could have done a bit better).
We bought it off of them in May of 2010 for $17,000 and that included a bunch of accesories he had purchased for it (RV cover, wheel covers, and various other items) AND the Equalizer brand WD hitch too ($500 value) that we use with it (which allowed me to sell the one I already had for a nice sum I might add).
In 2 years he lost $10,000 plus another $1,000 or so on the accessories and hitch..
I think you CAN mitigate deprecation to a degree on new units but you must pay a rock bottom price on them, maintain them very well, and then find the right situation when you end up selling them off.