> What is the best alternative for any models that seem new
> yet are obviously older calculators?
I think the alternatives are the same, whether they seem new or not. Sell them to the highest bidders here, or on EBay, clearly noting its condition and providing good digital images. Bidders here will bid higher for mint condition equipment (as will EBay bidders).
>What are the differences (if any) with the c, cv, and cx
>designations on a hp41 (and should they actually go for
>the price differences I see on ebay)?
Answer is right here:
http://www.hpmuseum.org/hp41.htm
"Differences between the C, CV, CX and Option 001
The HP-41CV was the same as the HP-41C except that it had four memory modules built in for a total of 319 registers. (With the four ports still available to add other modules.) The HP-41CX was the same as the HP-41CV but added the Time module (stopwatch plus clock with alarms), an Extended Functions / Extended Memory module, a text editor, and some additional functions. The Option 001 version of the HP-41C had no labels on the upper rows of keys or on the surrounding keypad. This version was meant to be heavily customized by the buyer. "
Since these are for the most part being purchased as "collectibles," the more rare versions will fetch a higher price.
Lots of useful information on this page:
http://www.hpmuseum.org/collect.htm