Buying advice

I would buy the rig that had the features I want/needed and not be concerned about eventual resale.
You are making a lifestyle decision were you should be looking for the maximum enjoyment for the time you use it, not for what you will get back when you sell.
Your enjoyment gain should outweigh your financial loss.

a used one.

If resale value is your main concern in a motorhome I'd look at some of the following lines: Barth, Blue Bird, Airstream. All brands that hold their values quite nicely. I'm sure there are others.

If you look at the depreciation curve for a MH you will see that the knee of the curve is about 4 years. The farther down the curve you go the less depreciation there is. So if resale is your main concern a high end MH that is 10 years old will depreciate a lot less than a newer one. A high end custom MH like NYCgrrl posted with a lot of mods would hold its value even more.

If you are interested in a Class C unit, consider a Lazy Daze. It takes 9 months to build one once ordered, so there is great demand for used ones in good shape. They also hold there value well.

For one or two years use, I would buy in at 7 to 10 years age, as the value will not change much in that short a time, particularly if you have patience to buy carefully and sell casually.

Brands, models, whatever fit my needs at the time, $100K probably a whole lot more than what I would need. When I was shopping in 2004-5 my needs would have been well met by 30-32 foot A gassers (Fleetwood's Bounder, Flair, Southwind Storm lines, Winnebago Brave, Damon Daybreak etc) or 28-30 foot C's. Even today, $30-50K will buy a lot of really good, really useful motorhome in the age range where depreciation has mostly leveled off.

$100K might get you something really nice in the 10-20 year old range, something that might cost a million to buy new today.

There is nothing you can buy new today for $100K, use for two years, and expect to get your money back.

I jumped in one time and bought a new Allegro Bay, and soon we realized we did not like the MH. We went back to a 5th and took a bad hit. I would shop for a Good Allegro, once you find the floor plan you want. There should be a lot of used on the market. Buying used I would definitely make sure I was going with a top quality unit. Probably a Allegro of some sort.

With $100K, i'd look at used Foretravels. Built well and well cared for ones do better on resale.

Ken

$100,00.00 will buy a good used Newmar.

I don't know squat about high end MHs but the best deals on bigger RVs in general are in snowbird states and more so in the spring when some of the folks are making their last trip.
I recall seeing a glut of RVs for sale in PHX in the late winter/spring.
And buy used. I've bought many toys, vehicles and my camper in my sig, just sold it for 25% more than I bought it for 18 mo and about 30 nights of camping ago. I always think like you are about minimizing the capital loss on depreciating assets.
Where you sell it makes a difference too. Prolly not as much market in AK for big pushers, I dunno, but I considered this when I bought mine in he birthplace of TCs and sold it where they cost a fortune to ship to.
Timing and location of the purchase and sale will have as much to do with your success as finding the right deal.
Another consideration in purchase location is the tax implications. Some states like WA tax the c&a out of you even on used purchases or transfers in to the state on RVs. Like 10% tax on the blue book on a used RV. WA excluded, if you buy private party and title it in the right state you can save a lot on taxes. Up to $10k in your case if you play your cards right! ;)