I just bought a Reslo with no cable that I haven't received yet. When I get it, I'm planning to try the method in the link below, using the Amphenol MC3F, the three pin version of the connector used on the older Shure 545, EV 644, etc.:
http://hinton-instruments.co.uk/wp/2010/06/09/reslo-rbm-repair-and-conversion/
(Disclaimer: I'm not affiliated with this site in any way, I just found it through a web search.)
Between this link and another website I also looked at (but unfortunately haven't been able to find again), I've gathered that the inside diameter of the Reslo is very close to the diameter of the Amphenol connector insert, making this a fairly easy swap.
I don't know if the threads on the outside of the connector are the same, but I guess I'll find out soon enough!
Part of the reason I decided to try this method is that I already have a stash of the three and four pin versions of these Amphenol connector that I've picked up at hamfests over the years, but they can be found on ebay for $10-$20 each. (So maybe $25-$50 total for both the female insert for the Reslo, plus the male mating connector for the mic end of a custom cable you'll need to make with an XLR male on the other end.)
Still not cheap, but the original Reslo cables I've seen have been ~$100 and up, and if you get lucky and find the Amphenol connectors for more like $15 each, that's still a pretty big savings.