How does one join the collector's society?

You should call Master Replica to sign up for their Collector's Society. You can't sign up through the web yet, but they are accepting phone orders. They said the Darth Maul .45 full size will ship in early June, and that it will be retired in December. The cost is $59.95, but I guess all of the coupons that come with the CS and the Maul mini should cushion the blow. Here is the number:
call 1-866-REPLIKA

Good luck!

Really?  A Maul double-bladed lightsaber that lights up and all that?  I don't know Dan.  I think you are lying to me.  LOL! I did see that damaged one.  What?  You have to by two of them that can connect to make the awesome double-bladed goodness?  

Just kidding.  I have no idea.  You are the Master Replica expert.

   Nice one B.  You can buy two battle-damaged minis (only a monkey would do that  ), or you could join the Collector's Society and get the full Darth Maul mini.  It should be substantially bigger than the other minis.  I am looking forward to mine! 

A Maul saber would be really cool, and I'll back up Jedidz23 on saying I read the same in the link he provided.  What would be a neat trick is to have the Maul saber able to split in the center allowing for a much smaller shipping box.  A simple twist lock device would probably be sufficient to secure the two ends to each other. 

Morgbug, that is a really cool idea!  You should let Amy from Master Replica know your suggestion.   

Are they ever going to release a double-bladed Darth Maul lightsaber?  I would love that!  I assume it would be roughly $250 though since the single bladed versions go for $120. 

Well monkey boy   , there was an article for that on sirsteve's website that featured an interview with the big cheese of Master Replica.  The LE already came out, and would run you around $450 or so on the secondary market.  The .45 is available now, but only if you join the Collector's Society (I did  ), and as for the FX, the interview said that is one of their most popular requests, and they are undecided on it, because it would be so long, but it would definitely be cool!!!

FYI Brian-Master Replica is selling a mini Maul now that is battle damaged (chopped in half by Obi-Wan).  I just ordered it, and should have it pretty soon.  I'll show you it when I get it. 

No real big deal to me, I just want a green FX saber.  If they do another version down the road, that's fine.  I'm not adamant about Luke, just want one of each color.

I hear ya buddy!  I will keep my eyes open, and if I hear anything, I will certainly let you know!

Very much so, Dan.  We have a lot of that here (especially in Morbug's case)...  

Thank goodness!  Life's too short not to mess with your buddies!   

... and I'd really like to start off with one of these FX sabers.  I really would like the ESB Luke one, but the ROTS Anakin one is a bit cheaper, and doesn't look too much different.  Plus, it is the "new" 3 battery style...although I don't know if that makes any difference or not .  Thanks again.

It isn't as smooth as the Anakin one, and is much heavier, but is still a great purchase!