Wow, you are the first person I have talked to that got an order for a gun turned down. There are indeed good used DW's on the market. I saw a couple either on gunbroker.com or auctionarms.com just in the last couple days. It seems the best prices were in the $550 range for the 44mag. Dan Wesson's are so rugged, that unless one has been severely abused, they are usually great used guns to buy. Every Dan Wesson I own was a used gun purchase, and all of them shoot like they were new. As for 44mag in a 445, it is like shooting 38's in a 357. The only problem is the fouling build up in the forward part of the cylinder. I would confine all 44 loads to jacketed bullets or maybe hardcast with GC and clean the cylinder after every use of 44 mag in it. In my DW's, I have never noticed any function or accuracy problems shooting 38's in a 357, 44sp in a 44mag, or 44mag in a 445. One word of caution, do not use extremely reduced loads in the 445 brass. Most manuals caution not to go below the minimum load listed. You get erratic burning and pressure spikes in the long cartridge with really small powder charges. You will notice most powders listed for reloading are large volume powders (h110, aa1680). The good part about that is you can use 44 magnum or even 44 special cases for reduced loads. The long 445 brass also lends itself well to large shot loads constructed with gas checks on the top and bottom of the shot, if big reptiles are a problem where you live.
I hate the factory isn't making 44mags anymore. They are fine guns. That just means I will appreciate the one I have all the more. Fortunately, most parts interchange between the 44 and the 445, with exception of the cylinder of course.
Best Regards,
Roll Tide