hello -
The best way is on Sportsmobile.com, "for sale" section ... track it for awhile. You have to get a feel for the strength of the market first. Back in 2007 used SMBs held their value pretty well bec there was more demand, but in the depths of the recession not as well. So, what is the market like today?
When I built mine in 2010, it took a little over 4 months to complete once they received delivery of the van. What is the lead time today? That will give you an idea of the market for SMBs.
Also, call up some of the sellers and tell them your dilemma and ask them what they think. All SMB owners are faced with the same dilemma when it comes time to sell. How did they arrive at their asking price?
Also, ask Sportsmobile what they think - not sure who to ask there. But they know what used ones are selling for.
I did this exercise in 2009 when I was debating new versus used. You can depreciate the Ford van part by itself as a starting point, but that is not completely accurate and is only 30% of the cost of the SMB if you get a full spec 4x4. My cost new out the door was about $100k and the Ford E350 was about $30k. So, the SMB part was about $70k. How much to depreciate the SMB part?
Probably something like 5% depreciation per year the first 3 - 5 years or so, then flatter after that. This assumes a CLEAN, LOW MILAGE SMB. This does not account for INFLATION.
Aren'y you glad you asked???
warholic